In phase measuring profilometry using traditional divergence lighting, for getting the height distribution of measured objects accurately, the mapping relationships between the reference plane coordinates and phase distributions must be calculated and stored in computers in the form of a data table for backup before measurement. The distributions of improved projection fringe are researched, so the stripes projected to the reference surface meet periodicity distribution. The phase distribution on the reference surface is a linear function of the coordinate. So the mapping relations between the reference surface coordinate and phase distributions are not needed to calculate and store in the computer in advance, and the measurement accuracy is improved and experimental apparatus are simplified. Experimental results show that the method is feasible and effective.