Abstract: Based on the actual measurement of 2 kW straight type fish aggregation lamps, we calculated the underwater illumination distribution of the squid jigging vessel Xinshiji No.52. The results show that when the total power was 360 kW, the iso-illuminance curve contours of 10.000 lx were at the depth of 32 m; in horizontal direction, it reached 80 m. The curve contours of 0.100 lx were at 50 m vertically and 260 m horizontally. When the total power was 180 kW, the curve contours reduced about 5 m in depth. Regarding 0.010 lx as the lowest limit to attract squid, if the power was increased from 180 kW to 360 kW, attracting distance could be increased from 620 m to 750 m, and 21.1% of effective attracting distance increased horizontally. If the lamps′ height increased for 0.5 m, 12.0% of the effective water volume increased. If the lamps′ space increased for 0.05 m, 4.4% of the effective water volume increased.