Abstract: Based on the underwater blasting from fish cage experiment in undocking channel in Guishan Niutou Island of Pearl River Estuary in December 2012, we analyzed the influence of blasting on nekton. The results indicated that the mortality of fish gradually decreased with increase of distance from blasting spot. Blasting had influences at different extents on fish body, gill, cavity wall, otolith and viscera, and the influences were closely related with distance from blasting spot, i.e., great influence from short distance and small influence from long distance. The direct weight loss and individual loss were 167.215 kg and 29 076 ind, respectively. Using regression empirical formula calculation and measurement of fish mortality, combined with the results of three experiments as well asthrough the two element linear regression, we studied the relationship among fish mortality, distance from blasting and explosive quantity to finally obtain anempirical mortality formula for swimming nekton.