Based on the generalized Huygens-Fresnel principle,the analytical ex pression of the cross- spectral density function for the partially coherent Laguerre-Gaussian (PCLG) beam pro pagating in biological tissues is derived,and used to study the effect of propagation distance z,topological charge m,radial index n,and spatial coherence length σ₀ on the normal ized intensity and phase evolution of the beam in the dermis of mouse tissue.It is shown that as the propagation distance incr eases,the intensity gradually decreases,the intensity distribution profile slowly evolves from mult i-peak shape to single- peak shape.Initial m-order coherence vortex and n circular edge dislocations evolve in to m+2n coherent vortices firstly,and then m+2n coherent vortices are new ly created.In addition,the larger the topological charge,radial index,and spatial coherence length,the slower the c hange in the intensity distribution and phase evolution.