In order to improve the ability of the new energy Internet to defend against external attacks, the author proposes a dual Markov chain-based FDIA detection method suitable for the new energy Internet. Taking into account the FDIA principles and characteristics of the new energy Internet, and the fact that the new energy Internet contains a large amount of measurement data and changing operating states, the data to be detected is mapped to two different state spaces, and two different Markovs are generated. The detector of FDIA is generated according to the accuracy of energy Internet operation state estimated by the model. The correctness and effectiveness of the proposed detection method are verified by experimental cases. Experimental results show: The proposed FDIA detection method has excellent detection probability and less detection calculation, the detection probability can reach 98.60%, and the false alarm probability is only 1.35%, compared with the support vector machine method, the calculation amount is reduced by an order of magnitude. It is proven that the method can meet the application requirements of the new energy Internet.