The invention relates to a carriage temperature control method. During heat supply, the temperature of cooling water of an engine is detected; when the temperature is lower than or equal to a first set temperature value, a heater is started to heat the cooling water, and a heat dissipation fan is turned off; when the temperature is higher than the first set temperature value and lower than a second set temperature value, the heater is started to heat the cooling water, and the heat dissipation fan rotates at a low speed; when the temperature of the cooling water is higher than or equal to the second set temperature value and lower than a third set temperature value, the heater is started to heat the cooling water, and the heat dissipation fan rotates normally; when the temperature of the cooling water is higher than or equal to the third set temperature value, the heater is turned off, and the heat dissipation fan normally rotates. By means of the heat supply control method, appropriate heat supply can be performed under different conditions, good comfort is guaranteed, the maximum energy saving is realized on the basis of comfort, and comfort and energy saving are both considered and balanced.