The timberline ecotone is important in climate change study as an early-warning region. The survival and development of planted forests at the tree line has significant effects on landscape ecosystems in natural reserves. Larix principis-rupprechtii, which has definite dominance on treeline of Wutai Mountain, was selected as the research target. A 50m×50m sampling plot was set up, and information about the species in the community were collected in 5 random quadrats (10m×10m) within the sampling plot, diameter at breast height (DBH) and location of trees were measured and recorded. Point pattern analysis and null models of Complete Spatial Randomness (CSR), Heterogenous Poisson (HP), and Random Labeling (RL) were adopted to analyze the pattern and process of the dead and surviving individuals of Larix principis-rupprechtii on 0-25m scales. The results of analysis were the following:According to DBH statistics, the average DBH of surviving trees was 11.54cm, and that of the dead trees was 8.27cm. As for the tree growth rate, the DBH of Larix principis-rupprechtii was smaller than that in other areas, and the slow growth was a result of adaptation to the timberline ecotone. Dead tree had larger clusters and aggregation at 0-15m scales, and surviving trees aggregated at the < 3m and 21m scales. The difference between the Heterogenous Poisson (HP) simulation pattern and the observed pattern for surviving trees was not significant, which meant that spatial heterogeneity explained the pattern of tree survival well. The Random Labeling (RL) simulation result showed that surviving trees had negative correlations with dead ones around 21m, and that mortality was caused by negative density dependence, especially for sapling trees. Meanwhile, results speculated that inter-specific interactions between shrubs and sapling trees had effects on tree death.