Study the affection of work performance and mechanical properties with different contents of fly in the self-compacting concrete. The mixture content of fly ash is respectively 16%, 20%, 30% and 40%. Carry on the experiment of slump, rate of spread, cube compressive strength, cube split tensile strength, prism axial compressive strength as well as the elasticity modulus of self-compacting concrete. Simultaneously obtain the corresponding stress-strain curve, and make the data fitting to it. The experiment and the analysis result show that there is a reasonable rang of mixture content of fly ash. When mixture proportion was suitable, the work performance of self-compacting concrete can be effectively improved, but the strength is also influenced. The early strength reduces much. This experiment provides the theoretical basis for reasonable application of fly ash in practical projects.