The energy regulation on the refrigeratory compressor is described. Both the energy-saving principle and performance of conversion compressor are discussed in detail. Two different modes of the control for compressor, frequency conversion cooling and full-frequency run, are compared here. It is concluded that frequency conversion is better than full-frequency on energy-saving. The energy saving and the most economical way of the conversion technology in refrigeration system are demonstrated by an example. Rate of return on investment is higher to apply frequency conversion for compressor in cold storage.