Pakistan made 308-5 after being put in to bat by the West Indies in the first one-day international of a three-game series at the National Stadium in Guyana on Friday.
Mohammad Hafeez top-scored with 88, with three sixes and six boundaries, while Shoaib Malik hit 53. Ahmed Shehzad made 67 and fellow opener Kamran Akmal 47.
Slow bowler Ashley Nurse claimed 4-62 off his 10 overs.
West Indies are seeking a clean sweep of the series to move ahead of Pakistan at number eight in the international rankings.
By the cut-off date of September 30 this year, the top eight teams, including hosts England, will automatically qualify for the 2019 World Cup.