Cavity method is widely used in microwave measurement of electromagnetic properties. In this research, a new double-ridged cavity method is proposed, which can enhance the operational frequency bandwidth. Based on the perturbation theory, the measurement equations required for permittivity and permeability extraction are developed. And for the accurate obtaining of electromagnetic properties, a calibration method is introduced to calibrate the shape factors. The proposed method is firstly simulated using the High Frequency Structure Simulator (HFSS) to demonstrate the linear relationship between the resonant parameters and the electromagnetic properties. Thereafter, a series of standard samples are tested by using the numerical simulation. Compared with the reference data, the calibration method can obviously improve the accuracy of electromagnetic parameters. Especially the error of the imaginary part in complex permeability is reduced front more than 60% to about 4%.