Disclosed is a cooling and heating system for a high-voltage battery of a vehicle, which includes: a radiator provided adjacent to a lower portion of a high-voltage battery module to radiate heat to outside air; an outside air cooling line configured such that cooling water circulates between the radiator and the high-voltage battery module, with a main valve being provided on the outside air cooling line; a bypass line configured such that a first end thereof branches from the main valve and a second end thereof is connected to the outside air cooling line to bypass the radiator, with a heat exchanger being provided on the bypass line; and a controller configured to control the high-voltage battery module to radiate heat through the radiator or to exchange heat with the heat exchanger by controlling the main valve when heat exchange of the high-voltage battery module is required.