High temperature molding technology was used to prepare YAG∶Ce phosphor film composite material with YAG∶Ce and silica gel as raw material, and the white light LED was packaged with blue LED light source. Based on the Mie theory, fluorescence spectrometer, rapid spectral radiometer and spectral distribution meter, the color parameters of film material and white LED were calculated and measured, and the influence mechanism of the particle size and concentration on the parameters were analyzed. At the same concentration, with the decreasing of the particle size, the mean free path decrease and the scattering coefficient and probability of absorption and conversion of the excited photon in the film material increase accordingly, The emission intensity of the film material, the luminous efficiency and homogeneity of light color of white LED are all increase correspondingly, the optimum value of the particle size is 8.7 μm at the same concentration; At the same particle size, along with the increasing of the concentration. The emission intensity of the film material, the luminous flux and photochromic uniformity of the white LED are also increase correspondingly. When the concentration is 4% and particle size is 8.7 μm, the white LED color temperature is 5 514 K, the luminous efficiency is 136.8 lm/W (@300 mA, 6.6 V), value of homogeneity of light color is 0.759, color coordinates x=0.332 2, y=0.359 6, the color point is located in the positive white light area near the blackbody radiation curve, which is the best concentration. Under different currents, the luminous efficiency and efficiency of white LED are linear, luminous flux: y=0.681 6x+63.121, R2=0.995 7, luminous efficiency: y=-0.062 8x+155.2, R2=0.991 6.This study shows the feasibility of flim material in white LED applications, and the relevant laws obtained are of reference for practical applications.