Abstract: According to the aging problem of power lithium-ion batteries, the LG-21700 lithium-ion battery with high specific energy was taken as the research object for studying the effect factors on its aging rate. The discharge capacity, ohmic resistance and polarization resistance were tested to characterize the degree of ageing respectively. Effects of five aging stresses on the aging rate were investigated and discussed based on the battery test system, which were charge rate, discharge rate, charge cut-off voltage, discharge cut-off voltage and ambient temperature, respectively. The results show that the capacity degradation, ohmic resistance and polarization resistance increase faster as the charge or discharge rates enlarge. Meanwhile, the charge rate is the crucial factor on the aging rate. When it reaches 1.00 C, the cycle performance of the battery becomes extremely poor. Moreover, the capacity degradation and internal resistance rise as the range between charge and discharge cut-off voltage enlarges. The charging method of constant current-constant voltage is beneficial to extending the lifetime. When the battery is aging in low temperature, the capacity degradation and internal resistance increase sharply due to the effect of lithium deposition. Considering the capacity characteristics, cycle performance and working temperature, it is found that charging and discharging between 30-35 ℃ not only delays the aging, but also improves its working performance and ensures its safety. In summary, the lifetime of battery can be effectively extended by reducing the charge/discharge rate and depth of charge/discharge or selecting the suitable ambient temperature.