A network selection method, comprising: determining each of networks running in a communication system satisfying requirements of a user when the user initiates a service or transmits a service; estimating an average energy efficiency of the communication system during service transmission after the user selects to access each of the networks; and selecting a network which makes the average energy efficiency of the communication system reach a preset threshold value to serve the user; wherein the estimating the average energy efficiency of the system during the service transmission after the user selects to access each of the networks comprises: estimating the average energy efficiency of system during the service transmission after the user selects to access each of the networks through a method of system energy efficiency prediction; wherein the estimating the average energy efficiency of the system during the service transmission after the user selects to access each of the networks based on the method of system energy efficiency prediction comprises: obtaining a throughput and power information of each network in each transmission time interval, TTI; selecting the throughput and power information during a first transmission time period, the first transmission time period comprises at least one TTI; estimating a throughput and power information of each network during a second transmission time period of the user, according to the selected throughput and power information; and calculating respectively the average energy efficiency of the service transmission of the communication system in the second transmission time period of the user after the user selects to access each of the networks, according to the estimated the throughput and power information. determining each of networks running in a communication system satisfying requirements of a user when the user initiates a service or transmits a service; estimating an average energy efficiency of the communication system during service transmission after the user selects to access each of the networks; and selecting a network which makes the average energy efficiency of the communication system reach a preset threshold value to serve the user; wherein the estimating the average energy efficiency of the system during the service transmission after the user selects to access each of the networks comprises: estimating the average energy efficiency of system during the service transmission after the user selects to access each of the networks through a method of system energy efficiency prediction; wherein the estimating the average energy efficiency of the system during the service transmission after the user selects to access each of the networks based on the method of system energy efficiency prediction comprises: obtaining a throughput and power information of each network in each transmission time interval, TTI; selecting the throughput and power information during a first transmission time period, the first transmission time period comprises at least one TTI; estimating a throughput and power information of each network during a second transmission time period of the user, according to the selected throughput and power information; and calculating respectively the average energy efficiency of the service transmission of the communication system in the second transmission time period of the user after the user selects to access each of the networks, according to the estimated the throughput and power information. estimating the average energy efficiency of system during the service transmission after the user selects to access each of the networks through a method of system energy efficiency prediction; wherein the estimating the average energy efficiency of the system during the service transmission after the user selects to access each of the networks based on the method of system energy efficiency prediction comprises: obtaining a throughput and power information of each network in each transmission time interval, TTI; selecting the throughput and power information during a first transmission time period, the first transmission time period comprises at least one TTI; estimating a throughput and power information of each network during a second transmission time period of the user, according to the selected throughput and power information; and calculating respectively the average energy efficiency of the service transmission of the communication system in the second transmission time period of the user after the user selects to access each of the networks, according to the estimated the throughput and power information. obtaining a throughput and power information of each network in each transmission time interval, TTI; selecting the throughput and power information during a first transmission time period, the first transmission time period comprises at least one TTI; estimating a throughput and power information of each network during a second transmission time period of the user, according to the selected throughput and power information; and calculating respectively the average energy efficiency of the service transmission of the communication system in the second transmission time period of the user after the user selects to access each of the networks, according to the estimated the throughput and power information.