Abstract: The continuous phase transition extraction was applied to extract Ganoderma lucidum polysaccharides(GLP)based on the mechanism of extraction and unsteady diffusion,the structural characteristics of the polysaccharide were analyzed. Based on Fick's second law,the mass transfer kinetics model of polysaccharides dissolution was established at different temperatures,flow rates and different extraction time. The molecular weight distribution,functional groups on the polysaccharide structure and observation of morphology of the polysaccharide were studied by high performance gel permeation chromatography(HPGPC),Fourier transform infrared spectroscopy(FT-IR)and scanning electron microscopy(SEM). The results showed that optional extraction of GLP was temperature of 373.15 K,flow rate of 28 L/h and extraction time of 190 min,the yield of GLP was up to 2.04%. The diffusion kinetic spherical model of the continuous phase transition extraction for polysaccharide was fitted to the equation of ln(C_∞-C)/C_∞=π²Dt/R²+ln(π²/6). The relative kinetics parameters including rate constant k,relative extraction rate y=(C_∞-C)/C_∞,half-life linearity y=-7.440 x+2864.4 and other kinetic parameters were calculated,the thermodynamics properties were investigated,respectively. The kinetics equation for extraction of polysaccharides from Ganoderma lucidum was fitted with the first-order dynamic model.HPGPC showed the molecular weight of GLP were from 1.35×10³ to 2.26×10⁷ Da. FT-IR results suggested β-pyran ring in GLP.SEM showed that GLP was flaky and the surface appeared dry folds. The kinetic model established lays the foundation for the optimization of the continuous phase transition extraction technological conditions and further theoretical study.