We present a empirical relationship between the superconducting transition temperature, Tc, and the doses of implanted ions, φ, namely Tc=1.13θDexp[-1/(A/(Φ+1)+B)] In comparing with experimental results, the calculated values of Tc by this expression are found in good agreement with them. Finally, we discuss the physical base of this relationship. The analysis indicates that the existance of the impurity band near the fermi surface results in the change of Tc.