The Mercedes driver led every lap from pole position for the second time this season to claim his fifth win of an increasingly one-sided Formula One campaign.
British driver George Russell emerged unscathed from a harrowing accident which saw his Williams hit by Antonio Giovinazzi's wheel after he crashed out.
Ferrari completed one of their worst weekends in recent memory with Sebastian Vettel and Charles Leclerc finishing in 13th and 14th respectively.
Daniel Ricciardo was fourth for Renault ahead of team-mate Esteban Ocon, with Red Bull's Alexander Albon sixth and Lando Norris seventh for McLaren.
Hamilton will head to Ferrari's home race at Monza in a week's time with a dominant 47-point championship lead after yet another crushing victory.
Despite the dominant nature of the win, Hamilton had fears for the state of his tyres in the closing stages.
"It wasn't the easiest of races," he said. "I had a lock-up into Turn 5 which gave me a vibration on the tyre.
"It was a bit of a struggle. I was nervous we might have a scenario like Silverstone where I had the puncture, so I was nursing it to the end.
"I know it is not what everyone wants to see - a Mercedes at the front - but no matter how much success we have we just keep our heads down.
"Back at the office, there are no guys celebrating. It is all about how we can win the next race and it is an incredible environment to be in.
"I am 35 going towards 36, but I feel better than ever so that is a positive."
After racing to his 93rd career pole with a scintillating track record of the 4.3 miles that make up this iconic venue deep in the Ardennes, Hamilton will have known the greatest threat to his 89th career win would come on the opening lap.
Hamilton kept Bottas behind at the short run down to La Source before continuing to keep the Finn at arm's length on the long run up through Eau Rouge, along the Kemmel Straight and into Les Combes.
Instead of challenging for the lead, Bottas came under pressure from Verstappen but managed to retain second place.
Hamilton was 1.5 seconds clear of Bottas after the opening lap. Bottas then appeared to ask for an extra engine mode to take the fight to Hamilton, one which was denied by the Mercedes pit wall.
"We have one push, no?" said Bottas. "We do - but we agreed not to use it against each other," replied his race engineer Riccardo Musconi.
"I have never heard of that," responded Bottas.
Unable to challenge Hamilton, the race settled into a steady rhythm before the Safety Car was released on the 10th lap.
Giovinazzi lost control of his Alfa Romeo on the exit of the 140mph Fagnes Chicane, crashing heavily into the wall.
Russell was following behind the Italian, and the front-right of his Williams was struck by Giovinazzi's left-rear wheel which had come loose from his damaged car.
The Williams driver then hit the wall on the opposite side of the Spa-Francorchamps track in his attempts to avoid Giovinazzi's machine. A breathless Russell reported over the team radio: "There was nowhere I could go, guys."
The leaders headed into the pits for their sole tyre changes. Hamilton held off a napping Bottas at the restart on lap 14 and cruised to a win which moves him to within two of Michael Schumacher's victory record.
Schumacher won 72 times for Ferrari but the German's former team are in crisis ahead of their home race at Monza and their 1,000th Grand Prix at Mugello a week later.
Vettel swore at his team over the radio, urging them to bring him in for a second change of rubber, before taking the flag in 13th.
It was even worse for Leclerc, who finished a place behind in 14th. Leclerc, who won here last year, had to stop for a second time as his Ferrari crew topped up pneumatic pressure on his engine.
Final Positions after Race (44 Laps):
1 Lewis Hamilton (Gbr) Mercedes GP 1hr 24mins 08.761secs
2 Valtteri Bottas (Fin) Mercedes GP 1:24:17.209
3 Max Verstappen (Ned) Red Bull 1:24:24.216
4 Daniel Ricciardo (Aus) Renault 1:24:27.638
5 Esteban Ocon (Fra) Renault 1:24:49.411
6 Alexander Albon (Tha) Red Bull 1:24:51.473
7 Lando Norris (Gbr) McLaren 1:24:52.535
8 Pierre Gasly (Fra) Scuderia AlphaTauri 1:24:56.132
9 Lance Stroll (Can) Racing Point 1:25:01.364
10 Sergio Perez (Mex) Racing Point 1:25:01.940
11 Daniil Kvyat (Rus) Scuderia AlphaTauri 1:25:18.961
12 Kimi Raikkonen (Fin) Alfa Romeo Racing 1:25:20.265
13 Sebastian Vettel (Ger) Ferrari 1:25:21.655
14 Charles Leclerc (Mon) Ferrari 1:25:23.681
15 Romain Grosjean (Fra) Haas F1 1:25:25.554
16 Nicholas Latifi (Can) Williams 1:25:26.556
17 Kevin Magnussen (Den) Haas F1 1:25:34.301
18 Antonio Giovinazzi (Ita) Alfa Romeo Racing 9 laps completed
19 George Russell (Gbr) Williams 9 laps completed
20 Carlos Sainz (Spa) McLaren 0 laps completed
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