Abstract：Based on the data investigated by light-iftnet in the Northwest Pacific Ocean in the autumn of 2016, the catch composition and biological characteristics were studied. The results showed that the average daily yield was 13.65t, the highest was 19.14 t appeared in October, the lowest was 10.58 t appeared in August. The average CPUE was 1 822.4 kg·h-1. The highest value was 2 492.2 kg·h-1 appeared in October, and the lowest value was 1 412.8 kg·h-1 appeared in September. The catch species was sixteen, which belonged to 8 order, 12 family and 16 genus. The main catch species were Scomber japonicus, Sardinops sagax , Cololabis saira and Ommastrephes bartrami, accounted for 72.00%, 19.41%, 7.94% and 0.58% in the total catch, respectively. Juvenile fish was accounted for a large proportion in population composition, and the rank of gonad maturity was at a lower level, which indicated that juvenile fish suffered severely damage.