Neon flying squid Ommastrephes bartramii an economically and ecologically important cephalopod, is one of main targeted species in the Chinese jigging squid fishery. In this paper, based on the samples collected by the Chinese squid jigging vessels during May to November in 2011 in the high seas of North Pacific Ocean (150°E-176°W), we compared differences in morphology and growth characteristics of beaks for two cohorts of O. bartramii. The results showed that females dominated in both the fall cohort and the winter-spring cohort. The morphological values in females' beak were larger than those of males, and the difference in these parameters between males and females in the winter-spring cohort was greater than that for the fall cohort. The upper hood length (UHL), upper crest length (UCL), lower crest length (LCL), lower wing length (LWL) had significant linear correlations with mantle length (ML) and significant exponential relationships with body weight (BW)(P < 0.01). The principal component analysis showed that the first principal component for the beak morphology of the fall cohort was related to UCL/ML of both males and females, and the second was UWL/ML. While for the winter-spring cohort, the first principal components of beak morphology were ULWL/ML and LLWL/ML, and the seconds were URW/ML and LRL/ML respectively, both represented the growth characteristics in horizontal and vertical directions. The morphology of beak for the two cohorts of female squid had significant differences, but no differences were found for male squid. The ANOVA indicated that the morphology of beak had significant differences among different ML groups(P < 0.01). However, the Least Significant Difference (LSD) analysis showed that the significant difference existed between the groups(P < 0.01)for all the morphological measurements except for UHL, URL, LHL and Lower Rostral width within the ranges of 250mm ML and 250-300mm ML for females of fall cohort. For the same corhot, the morphology of beak also had significant differences among different sex maturity stages(P < 0.01). The maturity stages I and II showed significant difference between the two cohorts, but no difference was found for stage III. In conclusion, the morphology and growth of beak for the two cohorts of O. bartramii differed with cohort, mantle length and sexual maturity.