Traction batteries are operated in severe working conditions of wide temperature range as the vehicles run in different seasons and regions, which effects battery performance deeply. Investigation on the effect of temperature under such circumstances on battery performance is very significant to promote the application of traction battery. In this paper, some tests are conducted on a ternary-material lithium-ion battery at various temperatures. The cycling performance and some significant parameters are evaluated at the whole temperature range, especially at the extreme temperatures (below -10°C or above 45°C). The results show that the battery performance becomes poor obviously at low temperatures, which is reflected in the decreased terminal voltage and the faded discharge capacity, and at too high temperatures (above 45°C), power and capacity also decrease, which happens in the later period of discharge process. The rise of pure ohmic resistance is the main factor to limit battery discharging at low temperatures, and the discharge performance becomes poor at the very high temperatures that may be attributed to the substantially increased polarization resistance in the later period of discharge process. Compared with the effect of high temperature on battery, the effect of low temperature is extremely conspicuous, and from the perspective of battery application on vehicle, the variation of battery performance should be paid more attention when the discharge operating temperature is below 5°C.