Based on the kastrov expression,the calculative method of the possible sunny day total and direct radiation received by wall surfaces with different orientations was obtained.Using vapor pressure to fit the parameter of expressions,we calculated the hourly solar radiation amount received by wall surfaces with different orientations at 704 stations of China,and analyzed its variations.The distribution of radiation exposure in the strongest hourly radiation over China was also analyzed.Results show that the sunny day solar radiation amount received by southern walls increases with latitude in winter and it is the largest among those recieved by walls with different orientations;and variations of the sunny day solar radiation received by eastern and western walls with latitude are relatively smaller than other orientations and its radiation amount is the largest in summer.