Abstract: To study the growth rule of seedlings of Idesia polycarpa Maxim. and to promote the development and utilization,investigation and analysis were made of growth traits of seedlings of I. polycarpa. from nineteen different families. The results showed that there were major differences in growth traits of I. polycarpa among nineteen different families,and a wide range of variation and a abundant genetic variation existed in the height and ground diameter of seedlings,which was good for choosing fine famillies. According to the results of correlation analysis, significant positive correlations were found between the seedling height and the seedling ground diameter,and week positive correlations were found between the ground diameter and the root cap. The family heritability of seedling height, ground diameter and main root length was 0.94,0.87 and 0.91 respectively, all of them were mainly controlled by their genetic character and belonged to a strong addictive genetic degree. The family Longheng 20,Longheng 27 and Hanzhong 6 were selected as fast-growing and good-adapting families according to comprehensively considering the seedling height and ground diameter factors.