As an intrinsically safe gas detection method, laser gas telemetry can perform real-time, online, non-contact, and long-distance detection, which has unique advantages. Based on non-cooperative Targets, a portable, lightweight, low-cost and practical handheld laser methane telemeter with completely independent intellectual property rights has been designed and developed. The temperature control chip of the telemeter adopts WTC3243 and the temperature control accuracy can reach 0.01 ℃. The transceiver integrated optical telemetry component of the telemeter adopts a parallel optical axis design. Through the standard gas comparison test, results show that the relative measurement error is within ±5%, the comprehensive measurement deviation is 293×10-6 m, and the goodness of fit between the telemeter measurement value and the standard integral concentration value is up to 0.999. After different telemetry distance tests, results show that the telemetry distance can reach 20 m, and the system has the consistency of different telemetry distance measurements. By simulating the actual environment test of methane leaking air mass, results show that the designed and developed handheld laser methane gas telemeter can be used for real-time, online, non-contact, and remote sensing of methane gas leakage in actual gas pipelines and other places, which also meets the measurement requirements.