Zaidi made 202, hitting 29 boundaries and a six during his 387-minute innings, as the hosts accumulated 398 for two in their allotted 90 overs, in reply to Zimbabwe's 215 all out on the first day.
The 23-year-old left-handed opener put on 158 for the opening wicket with Asif Zakir, who scored 61, as the inexperienced Zimbabwe bowlers toiled hard to get a breakthrough on Tuesday.
Zaidi, who hit 493 runs in just six games in Pakistan's first-class tournament last season, added 117 for the second wicket with Shahid Yousuf (36) and an undefeated 123 for the third wicket with Test discard Faisal Iqbal, who made 86 not out.
Alexandar Graeme Cremer took both wickets for the tourists.
Zaidi was delighted with his efforts. "I was positive right from the word go and now am hopeful that my innings will push my career forward," he said.
Each side was restricted to a maximum 90 overs in the first innings. There was no over limit for the second innings but the teams ran out of time.
Zimbabwe chose not to bat out the remaining 40 minutes of the final day.
Zimbabwe now take on PCB Patron XI in a four-day game in Lahore from Friday. They meet Pakistan in the opening match of the tri-series, also involving Sri Lanka, in Multan on September 30.