ELRF-J40 laser rangefinder module is developed based on our self-designed 1535nm erbium laser. It adopts a single-pulse TOF (Time-of-Flight) ranging method, with a maximum measurement range of ≥10km. The module consists of the laser, transmission optical system, receiving optical system, and control circuit board. It communicates with the host computer via RS422 serial port and provides test software and communication protocols for easy secondary development by users. The module features small size, light weight, stable performance, high impact resistance, and is Class 1 eye-safe. It can be applied in handheld, vehicle-mounted, and pod-based electro-optical equipment.