The Pacific oyster (Crassostrea gigas) is a major global aquaculture species and a commercially important shellfish species in China. Beautiful shell color and fast growth are two important goals in Pacific oyster genetic breeding at present. We initiated selective breeding of shell color traits via family selection in 2010, and obtained four kinds of shell color strains including white shell, black shell, golden shell and purple shell. In the present study, the selection response, genetic gain and realized heritability of mass selection for shell height based on second-generation golden-shell families were analyzed. The results showed that shell height of the selected strain was greater than that of the control strain during the grow-out stage and the selected strain presented significant growth superiority after 350 d. The average selection response, genetic gain and realized heritability were 0.549±0.277, 3.717%±2.611%, 0.339±0.171 respectively, during larval stage, and were 0.436±0.138, 8.253%±1.014%, 0.270±0.086 during grow-out stage. In addition, golden shell and golden mantle proportion in the selected strain were increased by 22% and 10% compared with that of control strain, respectively. The information obtained in this study is of great significance for the selective breeding of golden shell Pacific oyster.