Although the wireless private network is an important part of the middle and low communication access networks;its development is restricted by the limited spectrum.The dedicated band of230MHz can only get very low transmission rate and spectrum effectiveness.In order to improve the spectrum effectiveness and get higher transmission rate，carrier aggregation is suggested to be used in this band.According to the characteristics of230MHz band，this paper proposes a digital circuit to realize the functions of carrier aggregation.In order to test the effectiveness of the carrier aggregation at the power dedicated spectrum，the transmission rate is estimated and experiment was carried out on the new electric power wireless broadband system.The result shows that the spectrum effectiveness of the power dedicated spectrum has been distinctly improved by carrier aggregation.