The present study numerically investigates the effect of the wavy leading edge on hydrodynamic characteristics for the flow of rectangular wings with the low aspect ratio of 1.5 at one Reynolds number of 10 6 based on free stream velocity and the chord length C. The waviness ratio R w is defined by the span length of wing to the spanwise length covered by the waviness. Five different waviness ratios of 0.2, 0.4, 0.6, 0.8 and 1.0 at fixed wavelength of 0.2 C and wavy amplitude of 0.025 C have been considered. The smooth wing and R w = 0.2 revealed the similar variation of lift coefficient C L according to the angle of attack α, resulting in the same stall angle of 20°, where the maximum lift appears. The case of R w = 0.6 presented the earliest occurrence of the stall at α = 12°. The cases of R w = 1.0, 0.8 and 0.4 produced the same stall angle of α = 16°. In the post-stall region, C L for R w = 0.4, 0.6, 0.8 and 1.0 recovered and became larger than those of the smooth wing and R w = 0.2. A spiral formation of the limiting streamlines occurred in the wavy troughs, which derive relatively low pressure along the leading edge.