polymer foam and a method for preparing the same are disclosed . in the present disclosure , the method sequentially comprises the following steps : providing a polymer body ; performing a pressure - induced flow process on the polymer body at a first predetermined temperature and a first predetermined pressure for a pressure holding time , to obtain a polymer sheet ; and performing a foaming process on the polymer sheet by using a foaming agent at a second predetermined temperature and a second predetermined pressure for a saturation time , to obtain polymer foam .