Muscle spasticity is a common disorder of motor function. The electromyogram (EMG) and mechanomyogram (MMG) dualmodel information synchronous analysis has significant importance for the quantitative assessment of muscle spasticity. Aiming at the difficulty of synchronously acquiring the EMG and MMG signals with high signaltonoise ratio (SNR), in this paper a synchronous analysis method of EMG and MMG dualmode information with antipower frequency interference and light accelerometer signal correction is proposed, and a wireless multichannel EMG and MMG signal synchronous acquisition system is designed. Compared with the commonly used commercial EMG and MMG synchronous acquisition system (Delsys system), the EMG signal to noise ratio performance of the selfdeveloped system is similar to that of the Delsys system (both about 20 dB), and the effective frequency band (0~20 Hz) energy of the MMG signal is obviously higher than that of Delsys. The clinic test of the selfdeveloped system was conducted. For the healthy subject, the EMG signal to noise ratio of active elbow flexion is about 20 dB. For the three patients (muscle spasticity levels are 1, 1+ and 2 respectively, according to the modified Ashworth scale), the normalized EMG indexes are 054±005, 059±004,062±001, respectively (mean±std). The flexor MMG RMS (root mean square, RMS) of the three patients are 269±104 m·s-2, 319±113 m·s-2 and 489±119 m·s-2, respectively. Using the selfdeveloped system, the EMG and MMG information can be effectively used to grade the level of spasticity. The test results demonstrate that the proposed method can be used for muscle spasticity assessment and limb movement function monitoring.