A type of hydraulic pollutant decontaminating equipment was made in this paper. The decontamination and maintenance means were studied. The circulating decontaminating method was put forward and developed by modularized technique. The hardware of the decontaminating equipment was implemented with single-chip microcomputer and integrated circuit technology. The controlling application program integrated with fuzzy logic and reasoning function was developed. The practical use showed that the decontaminating equipment could be used in the maintenance of hydraulic circuit of bulldozer as well as the other engineering machinery, therefore realizing the quick decontamination and cleaning of hydraulic component and oil on-line purifying.