Abstract Heterojunction TiO 2 has attracted great attention in photocatalytic applications due to its high efficiency in the separation of photogenerated electron‐hole pairs and strong ability of light absorption. This work concisely summarizes the distinct crystal phases of TiO 2 and elucidates the prevalent methods employed in the synthesis of TiO 2 heterojunctions. Furthermore, the review highlights novel strategies for the realization of TiO 2 phase transformation, thereby contributing to a deeper understanding and advancement in the application of mixed‐phase TiO 2 photocatalysts.