Polymer-inorganic (P-I) soft-hard heterostructures & heterojunction photocatalysts, featured by large interfacial contact, efficient charge separation, broad light absorption and maximized redox capacity, have received great attention for their applications in environmental remediation and energy conversion. In this minireview, the classification and mechanism of P-I heterojunctions, i.e., type-I/II, p-n, Z-scheme and S-scheme heterojunctions, and their preparation methods are firstly introduced. Next, the photocatalytic applications of P-I heterojunctions, including water splitting, environmental remediation and carbon dioxide reduction, are extensively reviewed. Lastly, a brief summary and perspectives on ongoing challenges and opportunities to construct high performance P-I soft-hard photocatalysts are intensively highlighted. We envision this review will provide a picture of the state-of-the-art achievements and promote the photocatalytic applications of P-I heterostructures in energy conversion and environmental remediation.