According to the samples of Chinese squid (Uroteuthis chinensis) collected in the Northern South China Sea from April to June 2016, using the gradient forest method to screen the key environmental factors which affect individual growth, the relationship between daily increment of statolith and key environmental factors was established through the generalized additive model to analyze the impact of environmental factors on individual growth. The results showed that the squids hatched from October 2015 to January 2016, and the hatching peak was from November to December; sea surface temperature(SST),temperature of 25 m(T₂₅) and sea surface salinity(SSS) are the key environmental variables affecting the spawning population of the squids (November to December).When SST changed in the range of 23 to 28℃, the daily increment width of statolith decreased with the increase of SST. When T₂₅ changed in the range of 23 to 28℃, the daily increment width of statolith showed a gradual downward trend with the increase of T₂₅. When SSS changed in the range of 33.2 to 33.8, the daily increment of statolith decreased gradually with the increase of SSS. It can be inferred from the results that water temperature and salinity have significant effects on the growth of squids.