In order to investigate the determination of ginseng leaf area simply and quickly climax leaves of 5-year-old Panax ginseng were used to measure leaf length, leaf width and leaf area. Through the regression equation opti-mization, a mathematical model to predict leaf area was set up. The results indicated that the regression effect of re-gression equation model was satisfactory, that the simple leaf area, compound leaf area and the total leaf area ofplant were agreed well with the product of length and width of ginseng leaf（L·W）. The regression equation were asfollows: y=-0.0009x²+0.7033x+0.0295, y=0.0001x²+0.5934x+16.694 and y=-0.000 065 3x²+ 0.5154x+58.5838, re-spectively, the coefficients were 0.9908, 0.9764 and 0.9889, respectively. It was also discovered that compound leafarea could be estimated by determining length and width of the first, the second and the third single leaf as thepalm-like compound leaf was symmetrical. This model had a high prediction accuracy quickly and simply, whichcould be applied to scientific research and production.