The scientific measurement of reasonable annual harvesting volume of forests is the key to optimize forest structure and achieve sustainable development of forest resources.In this study,based on the forest resource survey data of Langfengguan state-owned forest farm in Guizhou Province,computer simulation was used to determine the reasonable annual harvesting amount of horsetail pine timber forest in this forest and compare it with the traditional formula method.The results showed that:1) the optimal managerial period and rotation period of 30 years were determined based on the simulation method,and the reasonable annual harvesting area was 19.88 hm² and the annual harvesting volume was 4 807.11 m³.2) During the simulation management in the next 30 years,the age group structure would be gradually stabilized,the proportion of middle-aged and near-mature forests would be gradually decreased,and the proportion of young and over-mature forests would be gradually increased.After the simulated management,the proportion of mature and over-mature forest area could be stabilized at 42.86%,and the age group structure would be ideally distributed.3) Compared with the traditional formula method,the simulation method has more scientific measurement mechanism,more flexible adaptability,more accurate measurement process and more objective measurement results.The use of simulation to determine the reasonable annual forest harvesting volume can provide a scientific reference basis for guiding forest management and realizing the sustainable use of forest resources.