The test of mechanical properties and durability performance and microscopic analysis are made on lining concrete samples of a tunnel in Southwest China, so as to learn the characteristics, mechanism and influencing degree of sulfate attack. The analytical results show that the inadequate compactness and large amount of limestone used for concrete are the main causes for sulfate attack. The authors suggest to make a proper selection of concrete raw materials and rational mixing proportion design and carry out curing and surface protection technologies to improve the antisulfate attack capacity of lining concrete of tunnel.