The further development of smart meters requires a certain period of long-distance communication capability after the interruption of external power supply, so as to backup the meter data and report the important events such as power failure. As a conventional backup power supply, both battery and electrolytic capacitor have disadvantages. The former has low service life, while the latter has too small capacity. This paper first discusses the feasibility of meeting the 16 years design life of the new generation smart meter by using the life estimation theory of super capacitor, gives the charging circuit design of super capacitor backup power supply to meet the life requirements , and solves the standby capacity of energy storage capacitor. Finally, aiming at the reality that the micro-power consumption circuit is difficult to be measured by conventional instruments, the circuit function is analyzed by using Spice analog circuit simulation tool and the actual circuit test is carried out to verify the feasibility of the circuit scheme. This paper has certain reference significance for the design of backup power supply of intelligent interconnected instrument equipment.