This paper is aimed at the durability of underground concrete structure,and the influence of water pressure (0,0.1 and 0.2 MPa) and fly ash content (10%,25% and 40%) on sulfate corrosion of concrete which were studied by means of laboratory simulation test technique.In the experiment,the sulfate corrosion depth and mechanical properties (compression strength and dynamic elastic modulus) of concrete after 60 days of corrosion were measured.The results show that the sulfate corrosion depth of concrete decreases linearly with the increase of fly ash content,and increases linearly with the increase of water pressure.The compression strength and dynamic elastic modulus of concrete decrease with the increase of fly ash content,and slightly increase with the increase of water pressure.In addition,the relationship between the compression strength and ultrasonic pulse velocity of concrete was analyzed.The result indicates that the influences of fly ash content and water pressure are not obvious.Based on the regression analysis,an exponential model between the compression strength and ultrasonic pulse velocity of concrete exposed to sulfate attack is established.