As a key subsystem of AMS-02(Alpha magnetic spectrometer),tracker thermal control system(TTCS)is developed to transport heat dissipated by the silicon tracker electronics to radiators that radiate the heat to deep space and to keep the temperature of the silicon tracker invariable. To enhance the reliability,a hierarchical monitoring strategy is implemented in the electronic subsystem of TTCS to monitor the system working status. The general architecture and components of TTCS are presented at first. Then the hardware structure of the monitoring system is described briefly. And the hierarchical monitoring model is designed and analyzed in detail,in which the FPGA-implemented health-guard strategy further improves the safety of the TTCS. Lastly,based on the ESTP(earth simulation testing platform)system,test methods and results are given to show the reliable operation of TTCS. This strategy has been implemented successfully in prototype design.