The aim of this work was to study the self-adaptive control system which could reduce the large deviations of the combination weigher’ s feeding amount that was caused by the slow change of feeding mechanism’ s parameters. This paper allowed the model reference adaptive control (MRAC) system to compensate for the deviations of the feeding speed, proposed the design method of the MRAC system for feeding mechanism, and performed simulation with the Matlab software. Assuming that the parameters of feeding mechanism changed at 1s, without the MRAC system, the deviations of feeding amount increased with the time within 2 s, and the relative error reached the maximum value of 41.38 % at 2 s. With the MRAC system, the deviations of feeding amount kept stable, and the relative error was 3.36 % at 2 s. When the MRAC system was adopted for the feeding mechanism of combination weigher, the feeding amount deviations caused by the slow change of the mechanism′ s parameters could be effectively reduced.