Abstract: If taper equation d=f(h, D, H) is constructed, merchantable height could be directly computed without deriving merchantable height equation h=g(d, D, H) from its corresponding taper equation d=f(h, D, H) when bucking with computer. Only the taper equation and the converted equation between DBH outside bark and DBH inside bark are necessary. Taking index of correlation and mean residual of errors for criteria and followed by residual analyses, the taper equation developed by Max and Burkhart in 1976 is chosen for Cunninghamia lanceolata and Larix olgensis. Merchantable volume tables are then constructed. Combining with theoretical height diameter curve, merchantable volume table for any stand can be constructed.