The phase unwrapping is a very difficult problem for profilometry of object containing depth discontinuities .The problem can be resolved with dual-frequency measurement technique. Two measurements with dual different frequencies cannot be contented with real-time demand. The new profilometry is based on compound grating, generated by computer software, projected by liquid crystal projector, so that the grating with different precision is easily created, conveniently changed .The same purpose is attained as capturing two different frequencies′ deforming gratings. Two phase maps are determined simultaneously, whose sensitivity to height variations is correlated with the frequency of pattern gratings. The phase uncertainty of the finest grating can be revised by the phase information coming from the coarse one. Finally, satisfactory experimental results are demonstrated. Meanwhile, it is verified that the new method has high speed, accurate unwrapping and extensive measure range.