Chasing 256, Bangladesh were bundled out for 119.
Mujeeb Ur Rahman, Gulbadin Naib and Rashid Khan picked up two wickets each to hand Afghanistan a comfortable victory.
Chasing a decent target, Bangladesh never looked in the contention as they lost their wickets at regular intervals.
Shakib Al Hasan (32), Mahmudullah (27) and Mosaddek Hossain (26 not out) mainly contributed to the Bangladeshi score. No other batsman clicked and went back to the pavilion one after another, posting single digit individual scores.
Mahmudullah and Mosaddek Hossain scored towards the end but the lack of support denied the run chase.
Earlier, Afghanistan rode on some brilliant batting by Rashid Khan (57 not out), Gulbadin Naib (42 not out) and Hashmatullah Shahidi (58) to post a decent score.
Besides the trio, opener Mohammad Shahzad (37) also played handsomely.
For Bangladesh, Shakib Al Hasan took four wickets while Abu Hider Rony scalped two wickets.
Brief scores: Afghanistan 255/7, (Hashmatullah Shahidi 58, Rashid Khan 57 not out; Shakib Al Hasan 4/42) against Bangladesh 119/10 (Shakib Al Hasan 32; Rashid Khan 2/13)