The invention discloses a method and device for determining a road surface temperature distribution law, and belongs to the technical field of traffic road surface detection. The method comprises the steps of collecting collected data of multiple sub-road sections of a to-be-collected road section by moving vehicle-mounted data collection equipment, wherein collected data of each collection spot of each sub-road section comprises an original road surface temperature, a collection time, and a first road section distance between the collection spot and the starting spot of the sub-road sections which belongs to the collection spot; correcting the first road section distance of each collection spot included in each sub-road section according to mileage pile stake marks of each sub-road section; according to a second road section distance of each making spot included in each sub-road section, and the corrected first road section distance, determining an average temperature of each marking spot of the sub-road section; according to a collection starting time, a collection ending time, a first collection temperature, a second collection temperature, and the average temperature, collecting the average temperature of each marking spot; determining the road surface temperature distribution law of the to-be-collected road section according to the average temperature of corrected marking spots of each sub-road section.