Beaks contain a lot of ecological information as feeding organ of cephalopods. According to the measurement of the morphological parameters of the beak from 303 Berryteuthis magister shevtsovi samples collected by Chinese jigging vessels in the Japan Sea in January 2018, the morphologic growth characteristic of beaks was studied. A total of 12 external morphological parameters of upper and lower beaks were analyzed by using SPSS. When the cumulative contribution rate of principal components was greater than 75%, the external morphological parameters with high coefficient were selected as the characterization parameters. Linear, exponential, power and logarithmic mathematical models were used to fit the relationship between external morphological parameters of beaks and mantle length (ML) and body weight (BW) by Excel. Akachi Information Criterion and correlation coefficient were used to compare the growth models. The principal component analysis showed the upper hood length (UHL), upper rostrum length (URL) and upper rostrum width (URW) could account for 80.71% of morphological characteristics of upper beak, and were selected main morphological parameters of upper beak and lower hood length (LHL), lower crest length (LCL) and lower rostrum length (LRL) could account for 81.57% of morphological characteristics of lower beak, and were selected main morphological parameters of lower beak (Table 2 and 3). Results of the analysis of covariance (ANCOVA) showed that there was no significant gender difference in the relationships between all morphological characteristic parameters and mantle length and body weight. According to equation fitting and Akaike’s information criterion, the relationship between UHL and ML was most suitable to be expressed by a linear equation, while the relationship between URL, URW, LHL, LCL and LRL and ML was most suitable for a logarithmic equation; the relationship between UHL and BW was described by linear function (Fig. 4), and logarithm functions were best for URL, URW, LHL, LCL and LRL. The determination of characteristic parameters and growth equation laid the foundation of population identification and resource assessment by using beak morphology in the further.