Accelerated corroding experiments of ordinary concrete and modified concrete(fly ash concrete, polypropylene fibre concrete and concrete mixed with fly ash and polypropylene fibre) immersed in two group of high concentrated mixed corrosive solutions were carried out. The two mixed corrosive solutions consist of SO2-4，Cl-，NH+ and Mg2+，Cl-，NH+ respectively. Change tendency of compressive strength, splitting tensile strength and elastic modulus of modified concrete varying with corrosive age(30, 60, 90 and 150 d) were obtained. The results show that corrosive effects of ions weaken each other in sulfate mixed solution and alleviate the damage process of concrete. On the contrary, they will aggravate in magnesium mixed solution and accelerate the erosion process. Resisting corrosion property of concrete is improved markedly by means of mixed in fly ash and polypropylene fibre, which results in 25%57% increase of corroded splitting tensile strength compared to ordinary concrete. The modified concrete was successfully applied in renovation project of municipal sewage plant with excellent anti corrosion performance and significant economic benefit.