According to the 356 Ommastrephes bartramii samples collected by Chinese jigging fleets in the north Pacific Ocean from July to October in 2012 (La Niña year in PDO cold phase),2015 (El Niño year in PDO warm phase) and 2016 (La Niña year in PDO warm phase). The statolith morphometrics by year and sex were analyzed, combined with the marine environment variation influence on the morphological variation of statolith. The results showed that significant differences of morphological variation of statolith were found by year and sex. The values of morphologic parameters of statolith in both cold (2012) and warm (2016) PDO phase of La Niña year were greater than those in El Niño year (2015). The result of principal component analysis indicated that total statolith length (TSL), wing length (WL), rostrum lateral dome length (RLL), maximum width (MW), wing width (WW) and rostrum width (RW) could be used as the characteristic parameters of statolith. The analysis of variance (ANOVA) showed that significant correlation was found between TSL, WL, RLL and MW versus mantle length (ML), while no significant correlation was found between WW and RW versus ML by year and sex. According to the SST and Chl.a mass concentration on the fishing ground, higher SST and Chl.a mass concentration in suitable range corresponded larger size of statolith.