Proper normalization of the measured capacitance data is a prerequisite in electrical capacitance tomography (ECT). The adaptive normalization model function relationship is proposed by using the mathematical relationship between parallel and series models in this paper. The factor of adaptive model is calculated based on the ratio of the minimum distance to the maximum distance from the unit to the electrical field centre line (EFCL) in the two regions divided by the electric field centre line. Simulation and experiments results show that the reconstructed image quality of this model is better than parallel and series model.