According to the samples of Ommastrephes bartramii collected by Chinese squid jigging vessels from July to October in 2007 in the Northwest Pacific Ocean,the ratio of statolith maximum width(MW)to total statolith length(TSL),as an indicator of shape change of statolith,was analyzed in different sexual maturitiy stages and individual sizes using the method of ANOVA and LSD.The results indicated that the statolith grew constantly in the entire life cycle of O.bartramii.MW/TSL values between sexual maturity stage Ⅰ and Ⅱ,Ⅲ,Ⅳ,Ⅴ showed significant differences,and MW/TSL values among sexual maturity stage Ⅱ,Ⅲ,Ⅳ and Ⅴ showed no significant differences.We conclude that the statoliths of O.bartramii hardly change their shape after the sexual maturity stage I.Between the four groups whose mantle length were less than 280 mm and most other groups,MW/TSL values showed significant differences,and MW/TSL values among groups whose mantle length were more than 280 mm,showed no significant differences.We conclude that the statoliths of O.bartramii hardly change their shape after mantle length of 280 mm.Mantle length of 200 to 280 mm corresponds with sexual maturity stage Ⅰ,and the period O.bartramii to with mantling length of 200 to 280 mm corresponds to the days for O.bartramii migrate into the subArctic waters.MW/TSL might serve as an valid indicator of sexual maturity and early ontogenetic shifts for the squid O.bartramii.