Abstract: By separating the target reflectance, incidence angle, and distance, the intensity value is expressed as the product of these three factors in the form of their polynomial functions based on the Weierstrass approximation theorem and a new terrestrial laser scanning (TLS) intensity data correction model is proposed. By using diffuse targets with different reflectance values, incidence angle and distance experiments are conducted to estimate the degrees and coefficients of each polynomial by the least squares adjustment and then the corrected intensity. The results show that compared with existing methods the proposed model can accurately correct the intensity value and can be extended to natural surfaces.