The invention discloses a method and a device for calculating the driving range of an electric car based on information fusion. The method comprises the steps of obtaining the current surplus available energy Ebat and the average energy consumption eavg of the power battery of the electric car, and calculating a calculated range value Srange, cal in real time according to the surplus available energy Ebat and the average energy consumption eavg of the battery, obtaining the real driving distance of the electric car within a predetermined time length before and calculating an accumulated range value Srange, cum according to the real driving distance, and calculating the driving range value Srange of the electric car according to the calculated range value Srange, cal and the accumulated range value Srange, cum, and displaying the driving range value Srange by use of an instrument. According to the method for calculating the driving range of the electric car based on information fusion, the fluctuation of the driving range estimated value is reduced and the estimation accuracy of the driving range is improved.