The work aims to study the effect of glycerin on the properties of lignin/PVA foam materials. PVA and lignin were dissolved by means of water bath heating, and then the performance was tested and characterized by adding different amounts of glycerin with a blank sample without glycerin as the control. With the increase of glycerin, the tensile strength of the foam materials increased first and then decreased. The tensile strength of the material reached the maximum (1.26 MPa) when the amount of glycerin was 8%. The elongation at break increased gradually from initially 37% to 167%. The appearance density decreased first and then increased and its minimum was 0.278 g/cm3. The water absorption decreased gradually and reached the minimum of 15.22%. The SEM test results showed that, the addition of glycerin improved the void structure of the foam materials, but adding too much glycerin would destroy the foam structure. TGA results showed that, with the increase of glycerin, the thermal stability of the composites decreased. The thermal decomposition starting temperature and decomposition temperature at the maximum rate were reduced gradually. In conclusion, glycerin has a greater influence on the performance of lignin/PVA foam materials. The addition of an appropriate amount of glycerin will strongly promote the mechanical properties, foam structure and thermal stability of the materials.