Abstract: LED lamp is a new type of light source which was introduced to light fishing, and its reasonable arrangement on boat will directly relate to the effect of luring fish.The article analyzes the Fresnel Phenomenon.The formula of relationship between each component of transmittivity and refractive indexs and angle of incidence when light goes through two different interfaces of medium can be get through the Fresnel's formula that is deduced from the principle of optical critical condition and the definition formula of transmittivity and refraction.And then, we can get the functional images that the transmittivity and refraction changed because of the variation of incidence angle when light passes through the sea surface by making use of MATLAB.The incidence when intensity of transmission beam reaches the maximum is 53.6°.This incidence angle can guide the installation of LED fish aggregation lamp in fishing boat.But the incidence angle could be changed to 36.4° for flat plate type LED fish aggregation lamp and could be changed to 23.6° for the three columns type of LED fish aggregation lamp.The included angle between two columns of LED fish aggregation lamps is 160°.