Japanese flounder (Paralichthys olivaceus) is one of the most important fishes for mariculture in China as it is fast growing and has high market value. However, in recent years, the Japanese flounder aquaculture encountered many problems such as disease, decreased growth rate and germplasm degradation etc. So, it is very important to breed new strains with high growth rate and disease resistance in flounder aquaculture. In the present study, the growth characteristics of 63 flounder families developed previously in our lab were compared. The body length and body weight of 80-230 d individuals from these families were measured and the results showed that the significant growth differences among families have been found. The average body length and average body weight of individuals from family with the fastest growth rate were 1.47 and 3.08 times than those of family with the slowest growth rate, respectively, and the absolute growth rate among these families ranges from 0.138 to 0.478. The multivariate analysis of variance (MANOVA) to family factors showed that the growth days of flounder family did not have significant influence on the body length and weight (P>0.05). The one way AVOVE and SNK analysis for 63 family growth characterization revealed that all families could be divided into 5 groups including the fastest growth, fast growth, normal growth, slow growth and the slowest growth group with significant difference (P<0.01). From these groups, eight fast growth families numbers of 19, 36, 51, 21, 69, 61, 64 and 81 were selected. The offspring growth characterization of seven cross combinations including RS♂×JS♀, RS♂×RS♀, RS♂×YS♀, JS♂×RS♀, JS♂×JS♀, YS♂×RS♀ and YS♂×JS♀ was analyzed with SNK method, and the results revealed that the JS♂×RS♀ hybridization family grew faster (P<0.05) and the obvious significant difference in the growth speed of family from different stock cross and same stock cross (P<0.05). The progeny testing of halfsib family suggested the JS29, JS12, RS41 paternity and RS75, RS28, RS86, JS21, JS22 maternity possessed the excellent growth genes owing to their offspring fast growth speed (P<0.05). Finally, based on these body length and weight data of the fastest and slowest growth family, the body length and weight relationship was constructed with correlation coefficient R²>0.5, the similar a value and b<3. And this showed that the family individual body length and weight had close relation and two kinds of families in stable growth environment were in allometric growth period.