Hydrogels are widely used in biomedicine because of their excellent biocompatibility, physicochemical properties, three-dimensional cross-linked polymer networks capable of absorbing and retaining a large amount of water, and various excellent properties that can be endowed to hydrogels through modification and material integration. This review focuses on the polymer compositions and applications of natural/synthetic hybrid hydrogels. Firstly, the physical and chemical crosslinking mechanisms of hybrid hydrogels with different natural/synthetic polymer combinations were discussed in depth. In addition, polymers for the preparation of natural/synthetic hybrid hydrogels and their advantages and disadvantages are widely introduced, focusing on polysaccharides, proteins, natural aromatic polymers and common synthetic polymers. Finally, this review will focus on the applications of natural/synthetic hybrid hydrogels in tissue engineering and delivery systems. Such as bone tissue engineering, nerve tissue engineering and drug delivery.