The invention relates to a microprocessor aging testing system and a testing method thereof, the microprocessor aging testing system comprises a microprocessor board, a crystal oscillating input and working state indicating board, a power supply system and an external program guide board. After the aging testing system is installed, microprocessors to be aged are mounted on the microprocessor board for initialization, an aging program in the guide board running the external program is led to the CACHE of the microprocessors to be aged for running, the working states of the microprocessors to be aged are monitored by the crystal oscillating input and working state indicating board during running, and when all the microprocessors to be aged run the aging program normally, the microprocessor board is put into an aging oven for the aging test. The invention utilizes the CACHE in the microprocessor to lead the aging program in an external memory into the CACHE through the external program guide board, so that the microprocessors can not access the external memory, thus, the problem that the aging test for microprocessor members can not run programs is solved, and the coverage rate of the dynamic aging is comprehensively improved.