Abstract: Based on a basic assumption that the effects of lamina situation on deformation mode under postbockling conditions is very small and by use of the displacement field of quisi-optimal lamina obtained by theory and experience, a engineering approaximate method determining optimal lamina parameters is given.The results show that the basic assumption and the method persented in this paper are right.As only one three-degree equation with one variable is to be solved in this method, the calculation is simplified significantly, and design cost and cycle can be redued ,so that the method will play an important part in engineering design.