Taking the dentine as the research object, a method to solve the light diffusion properties of anisotropic biological tissue is proposed. The diffusion tensor is introduced into the diffusion equation to describe the light propagation inside the tissue. Through theoretical derivation and considering light diffusion results of isotropic cubic tissue models, it is proposed that the ratio of diffusion tensor component can be expressed by ratio of long and short axes of forescattering contour ellipse incident by point light source. The experiment is performed to measure the forescattering light intensity distribution of dentine slice from two different directions incident by point light source of 10 μm diameter. The experiment result reveals that the ratio of diffusion tensor component of dentine is DyyDzz:Dxx=7.491.31. The orthogonal anisotropic diffusion equation is solved by finite element analysis method using ANSYS software by setting parameters as the obtained results. The simulated results are compared with the experimental data, and the correctness is confirmed. The study can deepen the understanding of scattering properties of dental dentine and gives the reference for the early detection of dental caries based on scattering effect.