Due to the limitations of system volume, the large field of view(FOV) detection method of laser fuze can not meet the requirements of system miniaturization. Aiming at the requirements of full detection in sagittal direction and narrow-FOV detection in meridian direction, a method of emission optical system with large FOV and miniaturization for laser fuze was proposed. The tunnel junction LD laser as a light source, a reasonable mode of FOV configuration was choiced, and an optical system with three-quadrant and sector-shaped emission was designed, which was characterized by small size, large FOV, reasonable structure, simple installation. The volume of single emission optical system was 8 mm×8.2 mm×15 mm, the single FOV in sagittal direction was more than 120°. The large FOV detection requirements of portable laser fuze whose diameter was Φ70 mm for air defense missile was satisfied, and the problem of miniaturization for full FOV laser fuze was solved.