Freshman Gary Harris scored a season-high 22 points, and the 18th-ranked Spartans used a 28-7 run in the second half to pull away.
The Spartans missed their first 10 shots from the field after halftime, but it didn't much matter in what quickly became a free throw contest. Michigan State finished 18 of 22 from the line, and the Boilermakers were 9 of 20 including 6 of 16 in the second half.
Harris, whose mother, Joy, was a standout at Purdue before playing for the WNBA's Detroit Shock, went 6 of 8 from 3-point range.
"I'm sure my mom was nervous with that being her alma mater, but I know she's happy with the outcome of the game," Harris said.
Izzo was happy with the outcome, but he said his team didn't play as well as the final score suggested. He wants Derrick Nix to be more efficient around the basket, Denzel Valentine to cut down on his turnovers and Branden Dawson to play with more energy.
"In the first half he didn't," Izzo said. "I thought the second half, he played with as much as I've seen him play with in over a year. It's a big difference in the game."
Dawson finished with 14 points and 11 rebounds for the Spartans (12-3, 1-1 Big Ten), who bounced back from a loss at Minnesota in their conference opener.
"The difference was Branden Dawson," Harris said. "He was a big spark for us. We just followed him."
A.J. Hammons scored 20 points for Purdue. The Boilermakers (7-7, 1-1) were coming off a win over No. 11 Illinois.