Temperature is one of the most important factors affecting a pest’s growth and development． We looked for a correlation between temperature change trends in Jianping county of Liaoning Province and the periods of occurrence of three behaviours of the larva of Dendrolimus tabulaeformis Tsai et Liu; climbing up the host tree，descending the host treeand overwintering． We compared recent temperature trends based on climate data from 1988—2009 with changes in timing of the selected behaviours of the larva ofD． tabulaeformis based on observations recorded over the sameperiod． The climate record indicates a significant warming trend in Jianping county of Liaoning Province during the 22 years from 1988 to 2009. Assuming a linear trend for temperature change we show that annual mean temperature，annual mean maximum temperature and annual mean minimum temperature all exhibit escalating trends，estimated at 0. 50℃ /10 years，0.59℃ / 10 years and 0. 36℃ /10 years，respectively． Seasonally，spring shows the highest escalation in temperature，summer andautumn show medium escalation and winter the lowest． Under climate warming，the periods of occurrence of climbing upand down the host tree and overwintering displayed changing trends． The behaviour of descending the host tree tends tobegin and end earlier and the duration of this behaviour decreases． The occurrence of climbing up the host tree tends to begin later and end earlier so that the duration of this behaviourdecreases． The duration of overwintering tends to