Based on their chemical structures, organophosphorus flame retardants can be classified into phosphate esters, phosphonate esters, phosphine oxides, phosphorus-containing heterocycles, phosphate ester polymers, and organophosphorus salts.

The selection of phosphorus-source compounds is crucial in the synthesis of phosphorus-based flame retardants; in addition to flame-retardant efficacy, factors such as reactivity, stability, and cost are also important considerations. Future development directions include the creation of high-molecular-weight organophosphorus flame retardants, organophosphorus oligomers and polymer-based flame retardants, reactive organophosphorus flame retardants, multifunctional organophosphorus flame retardants, and flame retardants incorporating multiple flame-retardant elements such as P, N, Si, S, and Br.