The invention provides a method and system using multivariate data to accurately calculate a road traffic blocking coefficient; the method comprises the following steps: tagging a plurality of detection points on city roads of an electronic map, using mobile phone position and speed data obtained from the mobile data center to calculate the vehicle drive speed in a scope, and obtaining first real time road condition data of the detection points according to the vehicle drive speed; using the internet to read at least three sets of real time road condition data so as to obtain second real time road condition data of the detection points, thus ensuring the real time road condition data of the detection points to be more accurate; fusing the first real time road condition data with the second real time road condition data, thus obtaining the final accurate road condition data; determining whether the detection point is a blocking source or not according to the road condition data of each detection point and the road condition data of the adjacent downstream detection point; if yes, obtaining the blocking coefficient of the blocking source according to the differences between the road condition data of the detection point and the adjacent downstream detection point.