Composite materials" grid structure without skin is the most efficient structure in composite materials grid structure.But compared with other composite materials grid structure,it is more difficult to design and shape. For the purpose of engineering application,this paper considers the problem of process forming,combining qualitative analysis with quantitative analysis.Optimized by five levels of grid form selection,typical structural engineering calculation,finite element optimization calculation, determination of engineering scheme and experimental verification.Finally comprehensive optimal effects is reached in various aspects such as structural form, design calculation,and process molding.It is verified that composite materials grid structure without skin can meet the requrements of engineering application.At the same time, the weak link of process molding is found,which created the conditions for the optimal structure.