In the network planning , introducing genetic algorithm improves accuracy and efficiency of network optimization.The slow computing speed is an obvious deficiency of genetic algorithm , which influences directly application effect of the algorithm .A method to solve the problem was proposed through analyzing the reason and mechanism of influencing computing speed of genetic algorithm.Experiments prove that the method is correct and effective .According to experiment results, factors to influence computing speed of genetic algorithm mainly relates to size of search space , select mechanism of paternal chromosome in the process of evolution , partial optimization accumulation resulted from crossed computation, and handling of invalid chromosome during evolution. Accordingly , search space is decreased by adopting restrict mechanism of problem space ;paternal chromosome is selected through dramatic threshold value ;through adopting roulette method for selection and adding optimum reserved strategy , diversity of colony is kept to break partial optimization accumulation, the optimum individual is insured to enter the next generation directly ;circular number is reduced through applying revised strategy to handle the invalid chromosome , and at the same time , diversity of samples is increased and partial convergence is avoided.Thus, the efficiency of network optimization is improved .