Objective To analyze the differences between the two kinds of hepatic fibrotic animal models in time effect and pathologic features in the course of development of liver fibrosis. Methods\ CCl 4 and PS ten week methods were used to make rat models of liver fibrosis. The development of pathologic features of liver fibrosis was observed at 6, 10, 14 and 20 weeks of model making respectively, and these presentations were analyzed by Masson stain and computerized image analyzing system. Results\ In CCl 4 method group, fibrotic pseudolobuli developed at 6 weeks during model making, became typical at 10 weeks, and got tranquilization thereafter, with ballooning degeneration of liver cells outstanding. On the contrary in PS method group, fibrosis occurred late in 10 weeks during model making, and developed from 10 weeks through 14 weeks though the model making had stopped; meanwhile ballooning degeneration was not presented. Conclusion\ There was indeed something different in the development of liver fibrosis in time effect relation and pathologic features between the two groups of model making. This indicated different mechanisms in the pathogenesis of liver fibrosis. The two methods of model making should be combined in the coming animal study of liver fibrosis; the prophylactic and treatment studies by anti fibrotic drugs should last no less than 14 weeks, and should begin 4 weeks ahead of the beginning of and the end of model making.