The cesium optically pumped atomic magnetometer is a quantum precision measurement device that operates based on optical pumping and magnetic resonance effects. It detects magnetic fields by exciting cesium atoms with a spectral lamp and probing their spin Larmor precession. This device exhibits advantages such as high measurement sensitivity, rapid response, and compact structure, and is widely applied in geophysical exploration, resource detection, and national defense security. This study systematically investigates the development of the cesium optically pumped atomic magnetometer, focusing on the core operational principles and breakthroughs in three key technologies: 1) The design of a magnetically clean probe, which optimizes the geometric structure and material to suppress external magnetic interference and enhance signal-to-noise ratio; 2) A magnetic-free temperature control system, employing high-precision temperature regulation modules to ensure the stability of atomic polarization; and 3) A low-phase-noise self-oscillating circuit, achieved through optimization of circuit parameters and feedback control strategies to minimize system noise and improve measurement sensitivity. During the integrated system development, the spectral lamp, sensor probe, and signal processing modules were co-optimized. Performance metrics were verified through calibration by 1st Class Weak Magnetic Metering Station of National Defense Metrology Station, demonstrating a measurement range of 10 000~120 000 nT and a sensitivity of 0.6 pT/Hz, which meet international advanced standards. Field tests under complex geomagnetic conditions confirmed the device′s stable performance, effectively addressing the demands of weak magnetic field detection for high precision and reliability. This research provides technical support for the domestic development of high-precision magnetic measurement equipment and contributes to the advancement of quantum precision measurement technologies in resource exploration and national defense applications.