Abstract: In order to calculate and predict the theoretical energy consumption of compressor, compressor performance was converted by using the similitude principle based on the physical property parameters of natural gas and the volume flow rate at the inlet of compressor in any working condition. Then, the characteristic equation was developed based on curve fitting to calculate the theoretical energy consumption of compressor. And finally, the compressor characteristic equation derived from curve fitting was verified on the basis of field data, and the error between theoretical energy consumption and actual value of compressor was analyzed. It is shown that in the allowable range of relative engineering error, this method is feasible. When the performance parameters of the compressor in any working condition is provided, the theoretical energy consumption of compressor can be calculated and predicted by using the compressor energy consumption calculation principle which is proposed in this paper. After the compressor runs for a period, its efficiency decreases due to internal scaling, wearing and other reasons, so it is recommended to introduce the correction coefficient to the characteristic equation of compressor power to make the theoretical energy consumption more accurate. (7 Figures, 4 Tables, 20 References)