Abstract: Optimal shape of multiple cutouts in square laminated composites panels with different lay-up configurations was sought for biaxial-shear stress loads using a non-gradient biomimetic technique named fixed mesh evolutionary structural optimization(FG ESO),which could achieve the most uniform Tsai-Hill factor.Material around cutouts where limited Tsai-Hill number is below rejection criterion was removed.This process was iterated until a steady state was reached,then rejection criterion was incremented and the iteration was continued until a predefined cutout area was achieved.In FG ESO,the node limited Tsai-Hill number determines the material needed to be removed rather than those of elements in conventional ESO,so the result boundaries are smoother than those designed by conventional ESO.The examples demonstrated the generality and robustness of this optimization procedure.The process of shape optimization of two adjacent cutouts in composites was investigated,and the results show some common rules of how the two cutouts affect each other.