Callcompletion rate is an important measure of the quality of the GSM networks.According to the basic theory of GSM network optimization,the paper analyse and studies the phenomenon of the low callcompletion rates,details the factors which affect the rates of GSM network optimization and proposes a set of feasible and effective optimization methods,and thus achieves an improved callcompletion rate,and an optimized  GSM network,and designs the software of  GSM network optimization. Finally,an instance of the GSM network in An Yang where exists low callcompletion rates is discussed,and the optimization software to improve the callcompletion rates is confirmed.