The invention provides a method and a device for adjusting voice data. The method comprises the steps of acquiring parameter information of a specified frame in voice data to be processed and first target tension or compression length of the specified frame, wherein the parameter information of the specified frame comprises a pitch period, first frame length and a first modification value; calculating the sum of the first target tension or compression length and the first modification value to acquire second target tension or compression length; calculating an adjustment parameter according to the second target tension or compression length and the pitch period, wherein the adjustment parameter is used for indicating the length of tension or compression performed on the specified frame; adjusting the length of the specified frame according to the adjustment parameter so as to acquire a second frame length and a second modification value, and updating a modification value of a next frame of the specified frame on which the tension or compression operation is performed according to the second modification value. The method provided by the invention solves technical problems that the tension or compression ratio of each frame cannot be changed in real time and that the tension or compression ratio cannot be controlled on the whole in related technologies.