In order to better understand the morphological growth characteristics of beak and fisheries biology, polynomial growth model was established for the relationship between mantle length and body mass for Loligo beka collected from fishery independent surveys by trawl net in the Bohai Bay from Jul. to Nov. 2021, and the size at first maturity was estimated. Wilcoxon rank-sum test was employed to analyze the influence of maturity and gender on the morphologic growth of beak. In addition, multivariate statistical analysis based on the principal components were applied to establish the relationships between morphologic straits of beak and mantle length or weight for Loligo beka. The analyses showed that polynomial growth model was more suitable for fitting the relationship between mantle length and body mass, and the sizes at first maturity was estimated at(3.522±0.009)cm,(3.505±0.026)cm and (3.513±0.016)cm for female, male and total Loligo beka, respectively. There were obvious differences in the morphologic between upper beak and lower beak. Some ratios between beak length indices, such as hood length and crest length, were nearly consistent with the change of sex and sexual maturity, but others were different, such as the ratios between upper crest length and upper rostrum length and between upper hood length and upper lateral wall length, and there were significant differences in gender and sexual maturity, respectively. Taking the coefficient of determination and Akaike’s information criterion (AIC) as the criterion of goodness-of-fit, the optimal relationships between morphologic indices of beak versus mantle length or weight were established by means of stepwise multiple linear regression. The information above mentioned suggested that the behavior of fishing Loligo beka with shorter than 3.513 cm in mantle length should been forbidden. The ratio of upper hood length and upper crest length could be used as stable beak index of the morphological characteristics of Loligo beka, the ratios between upper crest length and upper rostrum length and between upper hood length and upper lateral wall length could be used as the indexes of gender and sexual maturity, respectively. Besides, the relationships described by stepwise multiple linear function were more suitable for predicting the mantle length or weight on the basis of data of beak for Loligo beka.