Abstract: 13 half-sib families and 39 full-sib families of Mytilus edulis were established with the balance nest design in which each male mated with three females and the artificial fertilization technique.The shell height and length of each family were measured in 2,3,5,6 months.The heritability of the growth was estimated using the full- sib families theories.The results show that the maternal genetic variance component estimates are all significantly greater than those of paternal ones of each growth trait(P<0.05).The female genetic variance components have significant maternal effects(P<0.05),suggesting that the large non- additive genetic effects could not be differentiated from the available data,so the heritability of paternal half-sib families estimates in the narrow sense were precise unbiased estimator.The shell height heritability of paternal half-sib families estimates are 0.29,0.85,0.84,0.87 respectively.The shell length heritability are 0.27,0.87,0.86,0.85 respectively,during 2,3,5,6 months.There were significant additive genetic variance of the growth and different heritability of shell height and shell length,indicating that there is a great potential genetic improvement for the growth of M.edulis using the selective breeding.