Abstract: According to the observation data in fields during 1975–1976, we studied the redistribution character of solar energy in multi population and suggested the scientific basis and measures for solving the problems of "shading and wind sheltering" in the practice of production. We discussed the problems on' the orientation of planting. On the basis of practice, by the method of mathematic simulation a formula is introduced for identifying the conditions of day light under various planting schemes and given the scientific data for rational population.