Abstract: Variable-length chromosomes and their genes have been used for solving the shortest path routing problem of a genetic algorithm.Under random and fixed network,computer simulations with C and comparing with Dijkstra algorithm showed that most of the results are equal to the results of Dijkstra.Meanwhile,the results showed that the larger the population-sizing,the smaller the failure of ratio and the slower the rate of convergence.With population-sizing being fixed,the larger the population-sizing,the poorer the quality of results,and the higher rate of convergence.