The invention provides a method of carrying out early warning on a hazardous chemical substance transport vehicle parking in a service area. The early warning method comprises the following steps of carrying out geographical mathematical modeling on all the service areas in a target expressway to acquire a service-area geographical mathematical model in the target expressway; according to real-time positioning information of the hazardous chemical substance transport vehicle, calculating a running speed of the hazardous chemical substance transport vehicle and a running distance between two continuous positioning points, wherein a positioning time interval of the two continuous positioning points is greater than a preset time interval; according to the running speed, the distance, a preset speed threshold and a preset distance threshold, combining a current road congestion condition and determining whether the hazardous chemical substance transport vehicle is in a parking state; if the hazardous chemical substance transport vehicle is in the parking state, recording parking starting time and combining the service-area geographical mathematical model to determine whether the hazardous chemical substance transport vehicle parks in the service area of the target expressway; when the hazardous chemical substance transport vehicle parks in the service area of the target expressway, generating alarm information.