The invention discloses an elbow baffling structure of a nuclear power plant heat exchanger. The elbow baffling structure comprises a plurality of heat exchange tubes, a heat exchange shell pass whichis provided with a plurality of elbows and arranged outside the heat exchange tubes in a sleeving mode, and a baffling body which is arranged in the elbows and used for fixing the heat exchange tubes, wherein the baffling body comprises a positioning ring connected with the inner walls of the elbows, and a baffling plate closing the inner side of the positioning ring; the baffling plate is formedby splicing a plurality of baffling sheets; and the sides, close to each other, of every two adjacent baffling sheets are provided with a plurality of clamping grooves which correspond in a one-to-one mode and are used for fixing the heat exchange tubes correspondingly. Compared with the prior art, according to the elbow baffling structure of the nuclear power plant heat exchanger, by splicing the multiple baffling sheets into the baffling plate, the heat exchange tubes are washed by a shell pass medium laterally, and the heat exchange efficiency is improved; and the baffling sheets are provided with the clamping grooves for fixing the heat exchange tubes, thus, the heat exchange tubes cannot move radially, abrasion or deformation of the heat exchange tubes due to radial movement is avoided, thus, the product quality is improved, and the service life is prolonged.