Abstract: This study explored the change law changing pattern of pH value of steel slag leaching solution in the process of steel slag dissolution with an aim to study the influence of steel slag on environment.Specifically, it analyzed the influence law of steel slag basicity, magnesium oxide content, water temperature, steel slag particle size, liquid-solid ratio and other factors on pH value of steel slag leaching solution and conducted a comparative test with on-site steel slag.Results show that the pH value of the leaching solution after steel slag dissolution is in the range of 10~12, and with the change of time, the pH value first increases and then decreases.Increasing the basicity of steel slag and the content of magnesium oxide can increase the pH value of the leaching solution.The increase of water temperature, steel slag size and liquid-solid ratio can reduce the pH value of the leaching solution.