In this study, the cemented carbide without Cr addition (WC-Co) and the cemented carbide with 1% Cr addition (WC-Co-Cr) were used as the research objects. The effects of pH value and cleaning temperature of cleaning agent before coating on the corrosion resistance of WC-Co and WC-Co-Cr cemented carbide were investigated by means of atomic absorption spectrometry and electrochemical test. It was found that the WC-Co cemented carbide showed the best corrosion resistance when the pH value of cleaning agent was 11 and the cleaning temperature was 50 ℃, while WC-Co-Cr cemented carbide showed the best corrosion resistance at a cleaning agent pH of 10 and a cleaning temperature of 30 ℃. The Co was selectively dissolved as an anode on the surface of WC-Co cemented carbide. After the addition of Cr, the Cr2O3 passivation film was formed on the surface of cemented carbide, which effectively improved the corrosion resistance of WC-Co cemented carbide.