By combining the n-type Ti^3 + self-doped TiO₂ photonic crystal structure with p-type ternary semiconductor Cu₃SnS₄, a new potential nanostructure of photonic crystal structural-induced p-n coaxial heterojunction arrays (denoted as CTS/Ti^3 +-PhC-TNAs) was designed and successfully fabricated by periodic pulse anodic oxidation combined with in-situ self-assembly technique. To be used in photocatalytic H₂ production and organic pollutant removal after optimizing both the structure and Ti^3 + doping ratio, CTS/Ti^3 +-PhC-TNAs exhibited significantly enhanced photocatalytic activities of 159.29 ± 1.7 μmol·h^− 1·m^− 2 for H₂ evolution and 0.08308 h^− 1·m^− 2 for methyl orange degradation under simulated sunlight irradiation, which is 9.4 and 3.1 times higher than that of the PhC-TNAs. Detailed investigations revealed that the improved photoactivity of CTS/Ti^3 +-PhC-TNAs can be attributed to the accelerated photogenerated electron-hole separation at p-n heterojunction interfaces, the facilitated electron transfer along the coaxial heterojunction arrays and the enhanced light-harvesting through the unique designed photonic crystal composite structure as well. The present study shows a new insight and significantly improvement of photoactivity when Cu₃SnS₄is introduced to form a p-n coaxial heterojunction arrays with photonic crystal structured TiO₂, which provides a new means to design and fabricate novel film photocatalyst for high efficient solar energy conversion and photodegradation.