The continuous development of hydrogel towards the direction of high strength and toughness mechanical properties was promoted by modern productions and requirements. In recent five years, many novel design strategies which are introducing microphase separation structure into hydrogels for strengthening and toughening, have become a highlight of research. In this review, four design strategies to strengthen and toughen, including the homogenized network theory, sacrificed bond theory, concentrated cross-linking theory, "hard - soft" phase structure theory and the typical types of hydrogels, were mainly generalized. Four kinds of methods to prepare microphase separation structure were summarized as the orientation by external forces, the solvent displacement, the precipitation by temperature, the precipitation by ion diffusion. About strong and tough hydrogels with microphase separation structure, the toughening mechanism was summarized, the key of scientific problems was given and direction of development was proposed.