The invention discloses a large-area soil heavy metal detection and spatial and temporal distribution characteristic analysis method and system, and the method comprises the following steps: S1, setting a large-area soil heavy metal detection and spatial and temporal distribution characteristic analysis system; S2, constructing an analysis model for large-area multiple heavy metal element spatial distribution; s3, determining an analysis object; s4, sampling and detecting the urban surface soil in each gridding area; and S4, substituting the sampled composite detection data into the analysis model, analyzing the soil heavy metal content and geographic information, and drawing a total content distribution diagram of the four heavy metal elements. The system provided by the invention comprises a remote server, a plurality of front-end machines and terminal equipment. According to the method, the distribution characteristics of the heavy metal elements in the large area are analyzed by screening key detection objects, constructing a new mathematical model and comprehensively utilizing sampling point data and geochemical survey data, the area coverage of the analysis result is complete, the accuracy is high, and the automation degree of the analysis process is high.