The western stock of the winter-spring cohort of neon flying squid, Ommastrephes bartramii, is widely distributed in the Northwest Pacific Ocean, and its distribution and abundance are mediated by the climate variability and environmental conditions. Based on the fishery data during 1995-2011 from the Chinese Squid-jigging Science and Technology Group and the environmental data including the anomalies of sea surface temperature (SSTA), sea surface height (SSHA) and mixed layer depth (MLDA), we analyzed variability in the spatio-temporal distribution of environmental factors under different climate modes (warm and cold phases of the Pacific Decadal Oscillation, PDO). The results suggested that the catch per unit effort (CPUE) was high during the warm PDO phase and low during the cold PDO phase. Significant interannual variations were found in the SSTA, SSHA and MLDA, which corresponded to the variability of the warm/cold PDO phases. A negative correlation was found between the PDO index and the SSTA as well as the SSHA with time-lags of -9- -10 and -20-17 months, respectively, both with the highest correlation coefficient at the time-lag of 0 month; while the MLDA was positively correlated with the PDO index with a time-lag of -6-5 months, and the highest correlation coefficient occurred at the time-lag of -1 month. The empirical orthogonal function method was used to analyze the major mode of spati-temporal variability of SSTA, SSHA and MLDA, the first five modes of EOF for each environmental factor contributed to 78.73%, 32.82% and 64.57% of variation, respectively. Our findings suggested that shifts in the climate mode largely drove the variations in the environmental factors on the squid fishing ground, which led to significant abundance variability of O. bartramii in the Northwest Pacific Ocean.