Cal (8-3) led 30-27 at the break and used second-half runs of 13-2 and 10-0 to build a 70-48 advantage with 4:15 to go. Brittany Boyd had 13 points, seven assists and four steals and Courtney Range added 11 points.
The win allowed the Golden Bears to bounce back after losing to No. 1 UConn 80-47 on Dec. 22.
Danielle Fiacco and Linnel Macklin each had 13 points and Emily Homan added 11 points for Lafayette (6-5).
Macklin was 3 of 6 from 3-point range. She tied the game at 30-30 with a 3-pointer just 17 seconds after intermission, but the Leopards fell behind as they allowed Cal to shoot 16 for 31 from the field in the second half.