Two digital low pass filter used in Fourier Transform Profilometry is proposed and compared with Window low pass filter,verified by experiments.The two filters(high power index filter and rectangle cosine filter)have a adjustable flat pass band,flat and no sidelobes stopband,and the precipitous transition band links the pass band and the stopband slick and sly.Thus more useful frequency component can be kept as far as possible,the useless high frequency component is filtered quite well.The influence of side peak of low pass filter,designed by common window functions method,can be overcame.Experimental results prove that these two filter are simple in used,convenient in adjusting parameter,and have wide scope of application.There are many special characteristic in measuring the object details with large crook rate changing.