The basic properties of fish aggregating lamp and its fundamental theory are an important part of light lure fishing. The optical characteristics of domestic metal halide lamp (1 kW) were measured and analized including light distribution and attenuation coeffcient. Polar Function of light distribution curve was . Attenuation coeffcient was 0.128 1, 0.395 4 and 0.180 9 in the air, fresh water and seawater, respetively. There was no great difference in the depths greater than 30m when vessel was equiped with 130 or 100 lamps. Illuminaiton isoline of 130 lamps was 2m deeper than that of 100 lamps. This showed increasing light power counld not intensify underwater illumination, but enlarged attrative range in the upper layer. 50 m is enlarged when the total power increase from 100 kW to 130 kW. It was proved that domestic metal halide lamp (1 kW) not only got better results, but also had a long lifetime (3 000 h) that meet operation requirement.