The invention provides a preparation method of biodegradable poly butylene succinate (PBS) foam materials, which adopts a traditional chemical foaming method, improves and controls raw materials formula and technological conditions, and adds a cross-linking agent, a cross-linking auxiliary agent, a blowing promoter, a tackifier, an oxidation inhibitor, a foam stabilizer, a plasticizer and a release agent into raw materials except the PBS and the foaming agent so as to change fusant property of the PBS and adjust decomposition temperature of the foaming agent. The method comprises the following steps: firstly, evenly mixing various raw materials in a high-speed stirring machine; then carrying out plasticization in a mixing machine to obtain granules or sheets and carrying out chemical foam; and finally, obtaining PBS foaming materials. The PBS foaming materials have the advantages of controllable density, good mechanical proportionality, anti-chemical corrosion, easy processing, anti-vibration, heat insulation, biodegradation and the like, can replace polystyrene rigid foam, and are widely applied to the fields, such as various food packaging, medicines, medical apparatus and instruments or packaging manufacturing industry and the like.