County struck with two identical goals midway through the second half after the Unibond League side had given a good account of themselves.
Former Manchester United defender Graeme Hogg powered home a close-range header to break down Colwyn Bay's resistance in the 58th minute.
And then nine minutes later Ian Richardson rose to head home the second as the non-League side struggled to deal with County's aerial bombardment.
Both goals were set up by winger Steve Finnan delivering corners from the left-hand side.
Goals: Hogg (58) 1-0; Richardson (67) 2-0.
Notts County: Ward; Hogg, Pearce, Redmile, Strodder, Richardson, Finnan, Robinson (Derry, 74), Farrell (Jones, 46), Dudley, Robson (Hendon, 46). Substitutes not used: Lindley, Jackson.
Colwyn Bay: R Roberts; McGosh, Mann (Drury, 84), Graham, Caton, Price, Limbert (Donnelly, 24), G. Roberts, T. Jones, Congerton, Lawton. Substitutes not used: Woods, B. Jones, Nevitt.
Referee: T Jones (Barrow-in-Furness).
Bookings: County: Strodder. Colwyn: G. Roberts, McGosh, Caton.
Man of the match: Finnan.
Attendance: 3,074.Reuse content