Bell, who scored 126 from 117 balls in a knock that included 12 boundaries and a six at The Rose Bowl, justified his recall to the ODI team for the first time in nearly eight months as England reached 288-6 after being put in to bat.
The West Indies reply got off to a steady start as the top of the tourists' order all reached double figures with opener Dwayne Smith reaching 56 before he was bowled by Tim Bresnan, who was the pick of England's bowlers with figures of 4-34.
But the West Indies innings unraveled after a short rain delay that resulted in a revised target of 287 under the Duckworth-Lewis method, as its middle order failed to gain a foothold in the game with the last six wickets falling for just 45 runs.
Sent in to bat, England had lost Alastair Cook on the third ball of the innings. But Bell and Jonathan Trott (42) then put on 108.
Bell last played an ODI for England against India last October. He scored his other hundred in 109 ODIs at this venue, hitting 126 not out against India in 2007.
There are two more matches in the series.