Provided are a photo-thermo-sensitive genic male sterile line development method by using a No Primexine and Plasma Membrane Undulation (NPU) gene mutation and an application of the photo-thermo-sensitive genic male sterile line. The photo-thermo-sensitive genic male sterile line is constructed through inhibition of expression of an NPU protein related to plant pollen development. Also provided is a plant breeding method, comprising: maintaining plant sterility by inhibiting expression or activity of an NPU protein in a plant; then changing the plant from sterile to fertile by reducing the environment temperature for growth of the plant and/or reducing the irradiation time of the plant; and finally, maintaining the plant fertility and performing breeding.