Norwich kept their rampant hosts at bay during the first-half, but they had no response as the U's racked up three goals in a one-sided second period.
It was former Norwich old boy Jamie Cureton who set the ball rolling with an opening goal in the 52nd minute and after that he and Colchester never looked back.
Karl Duguid swung over a cross from the right wing and Chris Iwelumo did well to nod the ball down into the path of Cureton, who turned to lash home his 18th goal of the season.
Cureton is looking to become the first Colchester player to score 20 goals in a Football League season since Tony Adcock back in the mid-1980s.
The home side never looked back when Richard Garcia doubled the lead in the 64th minute.
All the hard work was done by Johnnie Jackson and his final cross was deflected only as far as Garcia, who rammed into an empty net.
It was one-way traffic by now and Iwelumo chalked up the third in the 73rd minute when he benefited from a bad error by City defender Andrew Hughes to beat keeper Tony Warner at the second attempt.
It was no more than Colchester deserved because earlier in the game they had hit the woodwork when Iwelumo headed Kemal Izzet's cross against the underside of the bar.
Norwich were below par, although they did have a couple of chances in the first half most notably when Darren Huckerby ran through on goal only to be denied by a great block from keeper Dean Gerken who saved with his legs.
Gerken also did well to keep out a long-range shot from Hughes, but this was really Colchester's day.
They have now won 13 of their 20 games at Layer Road and are well established in the top ten of the Championship.
And they might well end the season as the leading East Anglian club because they are now nine points clear of Norwich and eight clear of Ipswich with just six games remaining.