Abstract: Taking the natural secondary forest of Quercus franchetii in the mountains around Dianchi Lake as the research object, the characteristics of its spatial structure was studied using uniform angle index, neighborhood comparison and mingling intensity, and the correlation between spatial structure parameters and tree height or DBH was analyzed, simulating cutting to optimize the forest spatial structure. The results showed that most of the individual trees were in a random distribution state, and the horizontal distribution pattern of stand was of concentrated distribution type. The ratio of stand size was evenly distributed in different grades and was close to the mean state on the whole.The forest is mainly mixed with zero degree, and the spatial isolation degree is low. And there is a significant negative correlation between neighborhood comparison and mingling intensity. The stand structure of the secondary forest of Q. franchetii in the study area was unstable. According to the theory of structured forest management, by optimizing the simulation, the stand tends to be randomly distributed, the mixing degree is improved, and the stand stability is enhanced.