Abstract: Based on China's observational data from 1951-1990,after minimizing the possible biases caused by station relocation and urban heat island,the spatial and temporal distributions of trends for maximum and minimum temperat ures are studied.The results show that increasing trends of maximum temperature are in the areas west to 95°E,and north to the Yellow River,how ever,decreasing trends were observed in eastern China south to the Yellow river.Minimum temperatures are generally increasing throughout China,with dominant warming trends at the higher latitudes.This resulted in very obvious decreasing trend for temperature daily range.The quasi-oscillation cycles were consistent between the maximum and minimum temperatures,but asymmetric trends were obvious.The significant increase of minimum(night-time) temperat ures reflects the evidence of enhancement of green house effect.Further analysis showed that the changes of maximum and minimum temperatures are mainly related to sun-shine duration and atmospheric water vapor content.