The invention discloses a battery temperature maintaining system for an electric vehicle in a low-temperature environment and a control method of same, wherein the system includes a heat exchange box,a controller, a start switch, a protective switch, a temperature-limiting/maintaining switch, a temperature maintaining indicator lamp, a heating indicator lamp, an electric heater, a circulating power source and a temperature detector. In the low-temperature environment, the electric heater is started to heat a heat-transfer medium flowing through the electric heater; then the circulating powersource drives the heat-transfer medium to reciprocate cyclically between the electric heater and the heat exchange box; after the heat-transfer medium flows into the heat exchange box, heat exchange is carried out with a battery pack since the heat-transfer medium is high in temperature, and at this time, heat is transferred to the battery pack in the heat exchange box from the heat-transfer medium, and after the heat exchange is completed, the heat-transfer medium flows into the electric heater for being heated again, thereby durably heating the battery pack. The system can durably heat and perform temperature maintenance on the battery in the low-temperature environment, thereby greatly reducing the time that the battery works in the low-temperature environment and prolonging service life of the battery pack.