By using a series of unconfined compression test and scanning electronic microscopy technology, the paper studied the trength characteristics and microstructure of cement solidified nickel contaminated soil. The effect of nickel concentration, cement content and curing time on the cement solidified soil strength characteristics was discussed. Furthermore, the influence of nickel concentration on microstructure was also analyzed. The results show that the nickel concentration in soil interferes with the hydration process of cement which directly reflects the unconfined compressive strength development, stress-stain relationship and microstructure of the treated soil. The soil strength enhances with the increase of cement content and curing time. A linear relationship appears among the strength of cement treated nickel contaminated soil at different curing times. It analyzed the variation rule of failure strain of cement solidified nickel contaminated soil and E50. Along with the increase of nickel ion ,the failure strain increases and E50 decrease. The paper got the relationship between failure strain, E50 and unconfined compressive strength.