Abstract: In the light weight design of truss-likelanding-gear structure, the related specification on strength isconsidered. The bars'strength and critical loads are used as constraints and the minimumstructural weight design is achieved by shape and size optimization. Thedata obtained from an example agree with the results of staticforce test. Theoretical analysis and the flightof model planes carrying load show that the approach is not only feasible but alsoeffective. It can be used to design the landing-gear structure of a small or super light-weighted vehicle. %Finally, three conclusions have been drawn from this paper.