The invention proposes a motor system for separation of a chemical fiber and a rotational speed acquisition method of the motor system. The motor system is used for fiber separation of chemical engineering. During the running process of the motor system, the fiber separation degree is acquired in real time, the optimal rotational speed is acquired according to the fiber separation degree, so that fiber separation with maximum efficiency is achieved by the system on the premise of ensuring requirement of a user, namely, the motor system runs at the maximum power point. By the motor system, the current fiber separation state is acquired in real time, and the fiber separation state information is used as a variable incorporated into a hill climbing algorithm for rapid searching to obtain the optimal rotational speed. A traditional fiber separation system is changed to automatic control from manual observation, more intelligence is achieved, the separation quality of the chemical fiber is improved, so that the special requirements on fiber separation degree and process of the user can be met.