Abstract: Anti-interference is proposed as the key criterion for the lower-level electro-hydraulic control system in a two-level computer control system for the anthropomorphic operation of the digging bucket arm on the PC02 excavator, thus alleviating the effect of the sudden change of external load on the bucket's moving speed. With the state variables model and fuzzy/simulink-based model both developed for the electro-hydraulic system, the output scaling factor corresponding to the proportional coefficient of the conventional fuzzy-PID controller is adjusted online through the design of an auxiliary fuzzy inference controller (AFIC) so as to intensify the effect of proportionality. By simulation, the anti-interference characteristic of the electro-hydraulic control system was obtained when a sudden change of uncertain external load on the bucket happens, and the result also showed that the AFIC alleviates the effect of external load on the protruding velocity of piston rod and improves the time response.