Wireless monitoring sensor gradually replaces wired equipment for data support in petrochemical industry production. And wireless monitoring sensor with continuous energy supply is necessary and still faces great challenges. Thermoelectric generator makes it possible to power wireless monitoring sensor by continuously generating thermal energy from hot fluids in a collection petrochemical pipeline in any environment. The inability to obtain a larger temperature difference under TEG's high-temperature condition results in low energy efficiency, limiting the scheme's application. This work describes a thermoelectric generation system with an optimized heat sink for wireless monitoring sensor power supply at high temperature. The system is simple to install and use and is based on a high-performance passive heat sink with no power consumption and micro-vibration. We establish a practical prototype system to demonstrate performance and theoretical verification after analyzing the system's power loss to achieve high power and high efficiency. The experimental results show that the system proposed in this work can generate enough power to power the wireless monitoring sensor for 60 seconds. The minimum output power is 24.7"mW" at the hot-side of thermoelectric generation (TEG) temperature of 100 °C- 190 °C. The maximum power conversion efficiency in the considered input voltage range can reach an ideal value.