Based on the analyses of original taper functions, the improved Sohumacher equation with four parameters has been established as the taper equation of poplar in Jiangsu. Then, the outturn table for poplar in Jiangsu has been constructed. By experiment on the poplar stand of different siteindex, it shows that the equation fits the growth of poplar merchantable volume well, which can be used to estimate the yield of poplar stand in Jiangsu. The theory and method introduced in this paper have higher efficiency and also offers the good basic to construct yield tables of poplar stand. It has an important sense to enhance scientific management level and ensure estimating precision of yield prediction in poplar planning.