Biodiversity is the basis of sustainable development of ecosystem. Exploring pattern dynamics and formation mechanism of biodiversity is important for recognizing the structure and function of ecosystem. Three representative transects were chosen in Kanas Tourism District in Xinjiang Province, and the data of fire disturbance affair, species richness of tree and altitudinal gradients were collected and analyzed. The work was aimed to study the characteristic of species richness of tree along altitudinal gradients and its response to the fire disturbance in research area. The results show that the species richness of tree along altitudinal gradients displayed a distinct downtrend（P＜0.01）, but the altitudinal gradient was not the major factor for determining the species richness of tree (R2=0.2165）. There were eight fire affairs from 1880a to 1980a, and the mean interval was 14a. The fire affairs mainly occurred at the area below 1900m a.s.l. Species richness of tree at fire disturbance stand was higher than that at no-disturbance stand. The elevation was the fundamental factor to influence the altitudinal pattern of species richness of tree. Random of fire affair was the main factor which controlled species richness of tree at the area below 1900m a.s.l.