Abstract: Unsaturated polyester resin (UPR) and composites are light materials with high strength and have been widely used. However, the crosslinked three-dimensional network structure makes it difficult to recycle, which results in serious environmental problems. Liquid chemical approaches can efficiently degrade UPRs composites under mild conditions. This paper is aimed to review liquid chemical degradation and recycling methods for UPR composites, including alcohol degradation, amine degradation, supercritical & sub-critical degradation and ionic liquids & microwave degradation. Meanwhile, opportunities and challenges in the future are overviewed via systematical analysis of the strength and weakness of degradation methods.