The invention discloses a permanent magnet synchronous motor speed controller based on a novel extended state observer, which comprises a linear tracking differential controller LTD, a novel extendedstate observer ESO and a linear state error feedback control law LSEF. The linear tracking differential controller LTD receives an input rotating speed given signal omega ref and then arranges transition, a smooth transition signal is obtained, an output signal of the linear tracking differential controller LTD is compared with a feedback signal in the novel extended state observer ESO, and a system error e is obtained; the system error e is taken as an input signal of the linear state error feedback control law LSEF; and the total disturbance of the system is expanded into a state, the totaldisturbance is observed by the novel extended state observer ESO and compensated in real time, and finally the rotating speed output omega r of the permanent magnet synchronous motor is obtained. According to the invention, the problem that the peak phenomenon at the initial moment can be effectively inhibited while the observation precision is ensured in the initial observation stage of a traditional extended state observer is solved, so that the rotating speed response is not overshoot.