Abstract: A second-generation seedling seed orchard including 32 open-pollinated families of Eucalyptus urophylla was built at Gaoyao City, Guangdong Province to test the genetic performanee of families, which were selected from the superior trees in an improvement seed orchard. Compared with the characters of height, DBH, individual volume, survival rate, stem form, branch and blossom quantities among different families at 22 and 29 months. The results indicated that: (1)The most superior families by synthesis analysis are No. 21,11,1, 26,27,40,18 and 10 families; (2)With the 25%-elected rate, the genetic gain of volume of the superior families from seed orchard was estimated to be 12.96%～13.67%.