Abstract：Difference of optical properties of human normal bladder and human bladder cancer tissues at 476.5 nm, 514.5 nm and 808 nm radiation respectively in Kubelka-Munk two-flux model was studied. A double-integrating-spheres system and Kubelka-Munk two-flux model were used for the study. The results of experiment showed that there were very significant difference for the absorption, scattering, total attenuation, effective attenuation coefficients of human normal bladder and bladder cancer tissues at each laser wavelength of 476.5 nm, 514.5 nm and 808 nm radiation respectively in Kubelka-Munk two-flux model (P﹤0.01). Absorption coefficients of human bladder cancer tissue at 476.5 nm, 514.5 nm and 808 nm radiation respectively were obviously bigger than absorption coefficients of human normal bladder tissue at the same wavelength as that wavelength of radiating human bladder cancer tissue(P﹤0.01). Scattering coefficients of human bladder cancer tissue at 476.5 nm and 514.5 nm radiation respectively were obviously smaller than scattering coefficients of human normal bladder tissue at the same wavelength as that wavelength of radiating human bladder cancer tissue (P﹤0.01), and scattering coefficient of human bladder cancer tissue at 808 nm radiation were obviously bigger than scattering coefficient of human normal bladder tissue at the same wavelength (P﹤0.01). Total attenuation coefficients of human bladder cancer tissue at 476.5 nm, 514.5 nm and 808 nm radiation respectively were obviously bigger than total attenuation coefficients of human normal bladder tissue at the same wavelength as that wavelength of radiating human bladder cancer tissue(P﹤0.01). Effective attenuation coefficients of human bladder cancer tissue at 476.5 nm, 514.5 nm and 808 nm radiation respectively were obviously bigger than effective attenuation coefficients of human normal bladder tissue at the same wavelength as that wavelength of radiating human bladder cancer tissue (P﹤0.01). The results imply that it is a effective method to differential diagnosis of pathological bladder tissues by using a double-integrating-spheres system and Kubelka-Munk two-flux model by determining difference of optical properties of human normal bladder and bladder cancer tissues at 476.5 nm, 514.5 nm and 808 nm laser wavelengths respectively in vitro.