The YBCO films were prepared on LAO single crystal by TFA-MOD process. The structure and properties of YBCO films were investigated through changing the Y123 stoichiometry. It is found that higher JC values in self-filed of YBCO films are achieved by using the starting solution with the Ba ∶Y ratio of 1.5 ∶1. X- ray diffraction analysis revealed that Y2Cu2O5 phases are formed in the final YBCO films,which may lead to very effective vortex pinning and then enhance the JC of YBCO films.