This reprint mainly covers the topics of the synthesis of polyurethane and the preparation of its composite materials, as well as the latest research progress of polyurethane in different fields. This reprint collects the latest research progress of scholars from different countries across the globe, and each author has established good research findings in their studies, using various characterization methods to elaborate on the research phenomena in detail. I hope this reprint acts as a reference and provides inspiration for researchers engaged in polyurethane-related work.