Abstract: A double-integrating-spheres system and Inverse Adding-Doubling method were used in this experiment, The optical properties of native and coagulated human liver tissue at 532 and 1064 nm of KTP/YAG laser were study. The results of experiment showed that there is a 23.5 percent increase in the absorption coefficient for coagulated human liver tissues at 532 nm of KTP laser to compare with the absorption coefficient for native human liver tissues at the same laser wavelength (P﹤0.05), and there is a 34.3 percent decrease in the absorption coefficient for coagulated human liver tissues at 1064 nm of Nd:YAG laser to compare with the absorption coefficient for native human liver tissues at the same laser wavelength (P﹤0.05). There is a 4.50 times increase in the scattering coefficient for coagulated human liver tissues at 532 nm to compare with the scattering coefficient for native human liver tissues at the same laser wavelength (P﹤0.05), and there also is a 6.41 times increase in the scattering coefficient for coagulated human liver tissues at 1064 nm to compare with the scattering coefficient for native human liver tissues at the same laser wavelength (P﹤0.05). there is a 5.47 percent decrease in the anisotropy factor for coagulated human liver tissues at 532 nm to compare with the anisotropy factor for native human liver tissues at the same laser wavelength (P﹤0.05), and there also is a 1.95 percent decrease in the anisotropy factor for coagulated human liver tissues at 1064 nm to compare with the anisotropy factor for native human liver tissues at the same laser wavelength (P﹤0.05).