In order to reduce the hole leakage of deep ultraviolet laser diode (DUV-LD) in the n-type region effectively and optimize its performance, a novel M-shaped hole blocking layer (HBL) structure is proposed. By using Crosslight software，the rectangular, N-shaped and M-shaped HBL structures are simulated and compared. It is found that the M-shaped HBL structure can more effectively reduce the hole leakage in the n-type region, increase the radiation recombination rate in the quantum well, reduce the threshold voltage and threshold current of the laser diode, and improve the electro-optic conversion efficiency and output power of the laser diode. It is shown that the M-shaped HBL structure can effectively reduce the hole leakage of DUV-LD in the n-type region and optimize its performance.