Based on data information investigated twice in Xiaolongshan forest region of west of Qinling Mountains in 2008 and 2013,we chose trees Quercus aliena var.acuteserrata,Staphylea holocarpa and Acer davidii as research objects,and then changes of spatial pattern and correlation for the above trees in five years were analyzed with O-ring O(t) method of point pattern.Spatial pattern of Q.aliena var.acuteserrata must be discussed depending on different forest layers,but that of S.holocarpa and A.davidii and correlation of all population would not rest on forest layers for further study.The results show that:(1)Spatial pattern distribution of forest stand Q.aliena var.acuteserrata was,as a whole,random over five years.Q.aliena var.acuteserrata distributed randomly in the upper forest layer,more evenly in the middle and clumped obviously in the lower.The small number of S.holocarpa and A.davidii led to them with random distribution on most scales and then later,along with time variation,to them with lightly aggregated distribution on small part of scales.(2)For changes of spatial population correlation,there was negative correlation between S.holocarpa and Q.aliena var.acuteserrata on most scales for competition at the stage of sapling,and independent distribution on small part of scales to the certain stage of growth.The relation between Q.aliena var.acuteserrata and A.davidii,and S.holocarpa and A.davidii kept independent on the whole,but gradually the correlation existed on a small scale.The research indicates that,in different survey time,change of spatial distribution pattern for dominant trees in Q.aliena var.acuteserrata forest depended strongly on the scale,goodness of fit of the distribution pattern was high,and the forest stand on the whole was random distribution,namely spatial distribution pattern remained largely unchanged in five years;for principal species,the change of distribution pattern of Q.aliena var.acuteserrata conformed to growth regulation of communities and that of S.holocarpa and A.davidii was more affected by number of trees;change of forest spatial correlation was connected with population structure and its stage of succession;but for successional process of community,successional change of forest community in five years won’t enough represent successional rule of all forest stand,and the study must be still carried out over a long period.