Based on the MIS model, a simple method to extract parameters of SiC Schottky diodes is presented using the I-V characteristics. The interface oxide capacitance Ci is extracted for the first time, as far as we know. Parameters of 4H-SiC Schottky diodes fabricated for testing in this paper are: the ideality factor n, the series resistance Rs, the zero-field barrier height φB0, the interface state density Dit, the interface oxide capacitance Ci and the neutral level of interface states φ0.