Duke (8-1) bounced back from its first loss of the season at the hands of No. 2 Ohio State last week.
The Blue Devils owned a 37-30 lead with 5:20 to go in the opening half, and then blanked the Rams the rest of the way in the period to take a 47-30 advantage at intermission.
Andre Dawkins added 15 points for Duke while brothers Miles and Mason Plumlee both had 14. The Blue Devils won their 90th consecutive home game against a non-conference opponent.
Colorado State (5-4) was paced by Greg Smith with 18 points. Duke shot 56 percent from the field to 40 percent for the Rams.