The energy revolution and the digital revolution are integrated deeply. The creation of an Energy Internet big data ecosystem has gradually become a trend. The paper builds an evaluation system for the maturity of the Energy Internet big data ecosystem from the dimensions of ecological subject, key data, and overall environment. And then it uses big data capture, grade evaluation, tomographic analysis, mathematical statistics and other models, to propose the evaluation method of the Energy Internet big data ecosystem maturity. Finally, it takes Region A as an example to carry out an empirical analysis on the maturity of its energy internet big data ecosystem. The analysis found that the maturity of the energy Internet big data ecosystem in Region A is generally average and needs to be improved. Especially in terms of key data, there are still major deficiencies in data types and data quality. The degree of data sharing and mining has great room for improvement. The paper can provide reference for the digital transformation of energy and power companies and the energy industry innovative development.