Abstract: In order to explore the growth patterns,genetic variations and construction of breeding populations of Acacia melanoxylon,30 excellent families from the first generation clonal seed orchard of Acacia melanoxylon in Luoxi State owned Forest Farm,Quanzhou,Fujian Province,and 18 offspring young forests from excellent families introduced from Australia were tested in 2019. The results showed that the average tree height,breast height diameter,individual volume,and crown width of the 3-year-old Acacia melanoxylon experimental forest were 4.30 m,3.64 cm,0.0033 m³ and 2.30 m,respectively. The differences in the four traits among different families reached a highly significant level (P<0.01),with coefficients of variation of 31.95%,38.77%,87.20% and 30.74%,respectively. The variation in volume trait was the largest; the genetic heritages of tree height,diameter at breast height,volume,and crown width in the family were 0.5788,0.6268,0.6816 and 0.5220,respectively. The individual genetic heritages were 0.6776,0.5754,0.6808 and 0.4903,respectively. The genetic control of Acacia melanoxylon was moderate to strong at both the family and individual plant levels. Using genotype classification,the Acacia melanoxylon family can be classified into four growth types. According to the BLUP method,the breeding value of the family was estimated,and 10 excellent families of Acacia melanoxylon (5,37,16,22,13,38,11,32,47,2) were selected based on the volume trait (with a selection rate of 20%). These excellent families can provide material basis for genetic improvement of Acacia melanoxylon.