Based on the data of the sinking depth, gear operating and the ocean environmental data collected on light falling-net fishing in the South China Sea during March to April 2013, the relationship between sinking depth(sinking speed) and time was studied, and the relationship between the maximum sinking depth and the relating was analyzed using multiple regression statistics. The results showed that the maximum sinking depths of the both ends of the lead line were deeper than that in the middle; the maximum sinking depths of the both ends of the lead line were consistent; the sinking speed of the both ends of the lead line was faster than the middle; the sinking speed of the both ends of the lead line achieved the maximum at depth of 10 m, and the middle achieved the maximum at 5 m; the relationship between the sinking depth and time could be described using the formula: H=-0.0008t²+0.4766t+1.2063(R²=0.9985); and the relationship between the sinking speed and time could be described using the formula: V=-1E-07t²-0.0018t+0.5269(R²=0.8813);the results of the multiple regression statistics showed that the shooting duration, the direction angle between current and the wind, pursing time had a significant effect on sinking depth(P<0.001), and the current speed and wind speed had no significant effect on the sinking depth(P<0.1); there was no multicollinearity existed among the relating factors(κ=2.396<100). Our observations provide reference for ways to improve sinking characteristics in light falling-net fishing and a guide for fishing operations.