To explore the spatial and temporal changes of heat use efficiency (HUE) of wheat,maize,and wheat- maize rotation system and put forward effective measures for fully utilizing regional heat potential and improving HUE based on local production condition in Henan Province,the spatial and temporal characteristics of heat resources and HUE of wheat,maize,and wheatmaize rotation system were examined based on crop yield from the agro- meteorological observational sites and temperature data from meteorological stations respectively from 1981 to 2014 at 17 study sites in the province.The regional differences and the controlling factors of HUE were further revealed based on the statistical analysis results.The study showed that there were large spatial differences in calculated potential effective thermal time,actual effective thermal time,and heat use efficiency of wheat,maize,and wheat- maize rotation system.In 1981 to 2014,the length of growing period of wheat- maize rotation system increased slightly in Northern Henan while decreased in Western Henan.For Eastern and Southern Henan,the length of growing period of wheat-maize rotation system showed a trend of increase-decrease-increase and increased firstly and then decreased,respectively.With the selection of mid- late maturing varieties to adapt to climate change and improve HUE,growing period effective thermal time of wheat and maize increased in all the regions in Henan Province.The gap between potential and actual effective thermal times of wheat and maize increased from the north to the south and from the west to the east in the province.The gap between potential and actual effective thermal times increased for wheat but decreased for maize,which suggests that maize had higher heat use degree than wheat.Under the interactive impacts of crop yield and actual effective thermal time,heat use efficiency of wheat,maize,and wheat-maize rotation system was higher in the north and east of Henan than in the south and west of the province.From 1981 to 2014,potential and actual effective thermal times and heat use efficiency showed increasing trends with different increase rates caused by changes in growing period temperature,the length of crop growth period,and crop yield.In the future,there is an urgent need to improve the utilization of heat use efficiency especially in the Southern and Eastern Henan.