To study the influence of film on the characteristics of subwavelength grating,the growth of 100 nm Au film on the surface of subwavelength grating with sine groove shape and 80 nm groove depth was investigated. It was shown that the growth was profiling copy,the sine groove and periodic were keep unchanged almost. When sine duty cycle increased,the groove depth reduced and uniformity of groove depth got worse. The shadow effect generated by the microstructure of grating was proposed to explain these variations. The effect of sine duty cycle increasing on the spectrum of guided mode resonant filters was investigated too.