The effects of wing planform (shape and aspect ratio) on the aerodynamic force production of model insect wings in stroking motion were investigated, using the method of computational fluid dynamics. Ten respective insect wings were considered, they were the wings of fruit fly, cranefly, dronefly, hoverfly, ladybird, bumblebee, honeybee, lacewing (forewing), hawkmoth and dragonfly (forewing).The main results are as following. The force will be increased as the radius of the second moment of wing area is increased, but it has only minor effects on the force coefficients when the velocity at the radius of the second moment of wing area is used as the reference velocity. The force coefficients vary slightly, when aspect ratio increasing from 2.8 to 5.5. The reduction of 3-dimensional flow effects and the shedding on part of the leading-edge vortices (LEV) cancel each other, resulting in only minor change of the force coefficients.