The invention discloses organic phosphaphenanthrene derivatives, and a preparation method and application thereof. The structural formula of the organic phosphaphenanthrene derivatives is disclosed as Formula I, wherein the group disclosed as Formula II is from carboxylic acid derivatives or acyl chloride derivatives, the group A is from organic phosphaphenanthrene compounds, and the group A is connected with the group disclosed as Formula II through a P-C bond. The preparation method of the organic phosphaphenanthrene derivatives comprises the following steps: carrying out esterification reaction on glycerol and carboxylic acid derivatives or acyl chloride derivatives to obtain glycerol ester derivatives; and under the action of a catalyst, carrying out reaction on the glycerol ester derivatives and organic phosphaphenanthrene compounds. The organic phosphaphenanthrene derivatives can enhance the flame retardancy of the polymer, and can enhance the flame retardancy of the prepared material when being added as a functional aid for preparing high-polarity engineering plastics of PET (polyethylene terephthalate), PBT (polybutylene terephthalate) and other polyesters and PA6 (polyamide 6), PA66 (polyamide 66) and other polyamides.