Through solution method to obtain artificially synthesized C S H gel with different calcium silicon ratio and by means of XRD, SEM, XPS, TEM, ICP testing methods, the ability and its stability of C S H gel to fix heavy metal ions such as Cr3+, Cr6+, Pb2+, Zn2+, Cd2+ etc. were studied. The research results show that there are some differences in ability of C S H gel to fix heavy metal ion and its fixing mechanism with respect to different calcium silicon ratios. The C S H gel with high calcium silicon ratio has a higher ability to fix heavy metal ions. Different types and valence of heavy metal ions have different ways of combination with C S H gel and fixing ability. C S H gel has stronger ability to fix Cu2+,Cd2+, Zn2+ ions, but quite weaker ability to fix Cr6+ ion. In the hydration liquid phase, the ability of C S H gel to fix multi heavy metal ions is weaker than its ability to fix a single heavy metal ions. At the same time, if there is Cr6+ ions in hydration liquid phase, the ability of C S H gel to fix Pb2+ ion would be greatly reduced, while Cr3+ ion has less impact on it.