Abstract: There is nonradiative recombination in waveguide region owing carrier leakage, which in turn reduces output power and wall-plug efficiency. In this paper, we designed a novel epitaxial structure, which suppresses carrier leakage by inserting n-Ga0.55In0.45P and p-GaAs0.6P0.4 between barriers and waveguide layers, respectively, to modulate the energy band structure and to increase the height of barriers. The results showed that leakage current density reduced by 87.71%, compared to traditional structure. The output power reached 12.80 W with wall-plug efficiency of 78.24% at an injection current density 5 A/cm2 at room temperature. In addition, temperature drift coefficient of center wavelength was 0.206 nm/°C at the temperature range from 5 to 65 °C. The novel epitaxial structure provides a theoretical basis for achieving high-power laser diode.