The time resolved Monte Carlo method is used to study the time domain characteristics of light pulse propagation in tissue. The simulation results of Monte Carlo method are compared with the analytic results of diffuse theory. The relation between the optical parameters of tissue and the time resolved reflectance on tissue surface is discussed. The results illustrate that the time of maximum reflectance is mainly affected by the scattering coefficient, the slope of the reflectance decrease is mainly affected by the absorption coefficient. The g factor only affects the early data of the time resolved reflectance. The results in this paper show more promise to apply in the noninvasive measurement of the optical parameters of tissue and the oxygen saturation in arterial and skeletal muscle.