A hi-hat system of the present invention includes a support element, a connecting shank, a fixation element and a transmission element. The support element has a pedal and a rotatable axle. The axle inserts through the connecting shank and the fixation element in a rotational operative relationship. The transmission element connects between the pedal and the connecting shank. The fixation element is adapted to control a movement of an upper cymbal. The connecting shank has a longitudinal slot. The axle is movable between both ends of the longitudinal slot so that the distance between the axle and the transmission element is adjustable, further changing the drive ratio of the axle and the transmission element. As such, the percussion sensitivity of the cymbals is adjustable for the player to achieve better performance effect.