Abstract: 20Cr13 stainless steel was quenched at 1 030 ℃ and then tempered at different temperatures. Effect of tempering temperature on the microstructure and hardness was analyzed. Erosion-corrosion (E-C) performance of 20Cr13 stainless steel in 0.5M H₂SO₄ slurry containing silica particles was studied by using a home-made rotary erosion wear tester. The morphologies of the worn surfaces of the samples after E-C test were observed using scanning electron microscope(SEM), and E-C mechanisms were discussed. The results showed that the hardness of 20Cr13 stainless steel had the maximum value at tempering temperature of near 250 ℃.The characteristics of E-C for 20Cr13 stainless steel at different tempering temperatures were as follows: pure corrosion action was larger than pure erosion (wear), and at the same time erosion strongly promoted corrosion. The synergistic rate between erosion and corrosion accounted for about 80% of the total E-C rate. With the increase of tempering temperature, the microstructure of 20Cr13 stainless steel changed from martensite to troostite and sorbite, the carbides gradually grew, the corrosion rate increased, and the total E-C rate also increased. It was found that 20Cr13 stainless steel displayed the most excellent E-C resistance near 250 ℃ tempering.