Matings and crosses within and among two different geographic stocks from Shandong and Jiangsu populations in Meretrix meretrix were produced in order to breed new strains for farming. Two populations, designated S♀×S♂ and J♀×J♂, were from matings of wild populations of Shangdong and Jiangsu. Two populations, that was S♀×J♂ and J♀×S♂, were from crosses between Shangdong and Jiangsu respectively. The traits of fertilizing rate, hatching rate, growth of D-larvae and growth of juveniles (1-12 months age) were analyzed by ANOVA. The results showed that the fertilizing rate and hatching rate of matings and crosses were not significantly different at the end of second month. There were great changes of growth of juveniles in earlyterm (3-12 months). Growth of S♀×J♂, S♀×S♂ and J♀×S♂ had no significant difference from each other, but all had significant difference with J♀×J♂ at the earlyterm (3-12 months). The results indicated that there was different extent heterosis (6%-68%) for growth in F1 crosses. The uptrend among traits was wet weight being greater than other three traits of shell length, shell width and shell height respectively. There were obviously higher growth rate and lower variation coefficicent in S♀×J♂＞, which indicated the Shandong population would be a good parental stock as maternal for genetic breeding. Water temperature could affect growth of Meretrix meretrix significantly, and the growth rate reached a peak in October and November, but reached a nadir after December. Four populations gained were considered as the basic populations to breed new strains. Increased variation parameters in first filial generation(F₁) of cross could be a very good potential for selection of new strains.