At the limited roof north-south (N-S) width of a building, for the array with multirow collectors based on no shading at winter solstice noon and sloped at latitude, this paper studied the shading and the radiant energy striking on solar collector array. Based on Kunming solar radiation data, the annual and monthly solar radiant energy striking on multi-array collectors was analyzed and estimated, from no shading to partial shading by adding 1-3 collector row, at the slopes of 10°, 15°, 20°, 25°, 30°, 35° and 40°, respectively. The results showed that properly increasing the row number by reducing the slope of collectors was reasonable in order to get more annual radiant energy. Adding 1 row at 10 ° of slope was economical for Kunming, based on the 5-row array at 25°. And adding collector row by 20% at 10° of slope could increase the radiant energy striking on the array by 19%. At the limited roof north-south (NS) width of a building, for the array with multirow collectors based on no shading at winter solstice noon and sloped at latitude, this paper studied the shading and the radiant energy striking on solar collector array. on Kunming solar radiation data, the annual and monthly solar radiant energy striking on multi-array collectors was analyzed and estimated, from no shading to partial shading by adding 1-3 collector row, at the slopes of 10 °, 15 °, 20 ° , 25 °, 30 °, 35 ° and 40 °, respectively. The results showed that properly increasing the row number by reducing the slope of collectors was reasonable in order to get more annual radiant energy. Adding 1 row at 10 ° of slope was economical for Kunming, based on the 5-row array at 25 °. And adding collector row by 20% at 10 ° of slope could increase the radiant energy striking on the array by 19%.