The utility model relates to a burner capable of strengthening secondary premixing effect. The burner comprises a burner body, a connection nut and a diffusion tube, wherein the connection nut is sleeved on the inner side of the rear end of the diffusion tube, the rear end of the burner is sleeved on the inner side of the connection nut, a wind blocking piece is connected with the front end of the diffusion tube, and the above connection modes can be screw joint. Two lines of premixing holes are formed in the diffusion tube in a surrounding mode and are inclined holes with angles of inclination of 45 degrees optimally. By changing angles of the secondary premixing holes, full secondary premixing can be achieved, mixing is more uniform, burning is more efficient, therefore, burning efficiency is increased, and energy-saving and safe purposes can be achieved.