Based on the seawater salinity, temperature and squid catches collected during the period of the exploratory squid jigging in the mid-East of North Pacific in May-July in 2000, close analysis was made out of the distribution characterizations of the sea surface salinity, seawater temperatures of different depths, and squid fishing grounds. By using methods of cluster and correlation analysis, the correlation of the catch per unit effort (CPUE) to the sea surface salinity and the seawater temperatures of different depths were studied. The results indicate that squid fishing grounds are located in the folding zones of the lower salinity tongue and the warmer temperature tongue. The correlation of CPUE to 100m depth temperature is the most apparent, but there is still som good designation of the squid fishing grounds in the distribution mode of the sea surface salinity.