With the increasing awareness of sustainable chemistry and green chemistry, photochemical CO₂ fixation has drawn more and more attention in response to the need for renewable C₁ resources and inexhaustible clean energy resources. It is appealing to provide carboxylic acids and derivatives using CO₂ as a renewable feedstock, which is widely used in the manufacture of pharmaceuticals, pesticides, dyes and other fine chemicals. Classifying them by the types of reaction sites, this review presents an overview of the recent advances and achievements in the photocarboxylation of C(sp³)–X (X = H, N) bonds, C(sp²)–X (X = H, N, (pseudo)halide) bonds and C(sp)–H bonds with CO₂, with an emphasis on the mechanistic aspects of the reactions and a perspective on their future prospects, hopefully stimulating the further research and development of this appealing field.