In order to suppress the electron leakage to p-type region of near-ultraviolet GaN/InxGa1-xN/GaN multiple-quantumwell (MQW) laser diode (LD),the Al composition of inserted p-type AlxGal-xN electron blocking layer (EBL) is optimized in an effective way,but which could only partially enhance the performance of LD.Here,due to the relatively shallow GaN/In0.04Ga0.96N/GaN quantum well,the hole leakage to n-type region is considered in the ultraviolet LD.To reduce the hole leakage,a 10-nm n-type AlxGa1-xN hole blocking layer (HBL) is inserted between n-type waveguide and the first quantum barrier,and the effect of Al composition of AlxGa1-xN HBL on LD performance is studied.Numerical simulations by the LASTIP reveal that when an appropriate Al composition of AlxGa1-xN HBL is chosen,both electron leakage and hole leakage can be reduced dramatically,leading to a lower threshold current and higher output power of LD.