The invention discloses a heavy diffusion technology and a light diffusion technology in the manufacture process of a selective emitter solar cell. The heavy diffusion technology is applied below and around an electrode grid line, while the light diffusion technology is applied to a non-electrode grid line area. A high doping deep diffusion area is formed below and around the electrode grid line and a low doping shadow diffusion area is formed in the non-electrode grid line area by changing temperature, air flow quantity and technological time of the two diffusion technologies. The technologies solve the problem that the traditional one-step diffusion technology cannot reduce contact resistance on the surface of a silicon slice and a dead layer simultaneously, and have great meaning to the improvement of the overall performance of a crystalline silicon solar cell.