[Introduction] In view of the economic benefits of AGC frequency regulation project of combined energy storage in Guangdong coal-fired power plant, the method of establishing typical engineering cases is demonstrated. [Method] This article summarized the latest version of frequency regulation auxiliary market revenue settlement rules in the southern region and calculated the frequency regulation performance index of typical 2 × 600 MW coal-fired units using lithium iron phosphate battery energy storage in Guangdong Province, then established a revenue model, estimated or assumed the key parameters such as cost, mileage, clearing price, running time, etc. Finally, under the contract energy management mode, it calculated its economy from the perspective of investors and analyzed the changes of financial index under different total investment, operation year and revenue sharing. [Result] The results show that in the measured case, except for the first sharing scheme, the internal rate of return of capital in other scenarios all exceeds 7%. [Conclusion] The frequency regulation project of lithium iron phosphate battery energy storage in Guangdong has a good return on investment within four years. After that, investors can still be attracted to participate in this project with the decrease of total investment and the increase of share