Disclosed are method and an apparatus for analysis of an interface state of a MIS-HEMT device. By means of establishing an equivalent model of MIS-HEMT(s) that includes equivalent circuits representing a dielectric layer, a barrier layer and a channel layer, plotting a group of a capacitance-frequency function curve and a conductance-frequency function curve that can be best fitted to the measured capacitance-frequency scatter diagram and the measured conductance-frequency scatter diagram via the equivalent model, taking such best-fitted group as the fitted function curve group, and calculating parameters about the interface state of MIS-HEMT(s) according to the group of assigned values corresponding to the fitted function curve group, the parameters of the analyzed interface state can be more accurate since the fitted frequency function curve group can, with the aid of the equivalent model, simultaneously fit the measured capacitance-frequency scatter diagram and the measured conductance-frequency scatter diagram.