The invention discloses an electrical impedance imaging based oxidation degree monitoring method for a high temperature part of a composite material. The method comprises the following steps that an electrode is manufactured; a multichannel hardware test and measurement system is established; real-time electrical impedance imaging software is designed; relation between the resistivity and oxidation degree is established; and the oxidation degree distribution condition is obtained from a resistivity distribution calculation result. The method can be used to synchronously, accurately and indirectly monitor the oxidation condition of the high-temperature part according to a real-time calculation result of resistivity distribution of the high temperature part of the ceramic-based composite material as well as change relation of the resistivity with the oxidation degree.