The present invention relates to the field of on-board vehicle devices. Provided are a vehicle cooling method and a temperature adjusting system. The method comprises: recording a cellphone positioning information receiving terminal of a user, recording a method for determining whether the user is returning to a vehicle, and recording a temperature adjustment mode; reading information from the information receiving terminal and determining whether the user is returning to the vehicle; if not, then remaining as is; if so, then measuring a current temperature within the vehicle and determining whether the temperature is 20 degrees or greater; if not, then remaining as is; if so, then configuring, according to a temperature condition, a cooling mode of an on-board air conditioner, and activating the air conditioner. By receiving cellphone positioning information, the invention can determine whether a user is returning to a vehicle. If the user is determined to be returning to the vehicle, then the invention configures, according to a temperature within the vehicle, a cooling mode of an on-board air conditioner and activates the air conditioner beforehand. The invention thereby realizes prompt and active temperature adjustment within the vehicle, and prevents overly high temperatures when the user returns to the vehicle.