A method for load balancing among a plurality of servers, the method being applied to a Global Load Balancing device (11, 12, 13) in a multi-data center (1, 2, 3) environment under which each data center (1, 2, 3) comprises at least one Server Load Balancing, SLB, device (22, 32), the method comprises: receiving, by the GLB device (11, 12, 13), detection results of performance of a plurality of servers sent by each Server Load Balancing device (22, 32), wherein the detection results comprise a performance parameter and a corresponding IP address of each server of the plurality of servers; determining, by the GLB device (11, 12, 13), which server of the plurality of servers has a highest performance among the plurality of servers according to the performance parameters of the plurality of servers sent by the SLB devices (22, 32), and storing the IP address of the determined server; and receiving, by the GLB device (11, 12, 13), an access request from a client, obtaining the stored IP address of the determined server, and sending the IP address of the determined server to the client; wherein receiving detection results comprises: sending, by the GLB device (11, 12, 13), an instruction to each SLB device (22, 32) to set detection parameters, the detection parameters comprising at least a detection method, wherein each SLB device is to: perform an initialization configuration based on the detection parameters, and detect the results of performance of the servers in a data center at which the SLB device is located according to the detection parameters; and sending periodically, by the GLB device (11, 12, 13), a request to each SLB device (22, 32) in turn to obtain the detection results of performance of the servers receiving, by the GLB device (11, 12, 13), detection results of performance of a plurality of servers sent by each Server Load Balancing device (22, 32), wherein the detection results comprise a performance parameter and a corresponding IP address of each server of the plurality of servers; determining, by the GLB device (11, 12, 13), which server of the plurality of servers has a highest performance among the plurality of servers according to the performance parameters of the plurality of servers sent by the SLB devices (22, 32), and storing the IP address of the determined server; and receiving, by the GLB device (11, 12, 13), an access request from a client, obtaining the stored IP address of the determined server, and sending the IP address of the determined server to the client; wherein receiving detection results comprises: sending, by the GLB device (11, 12, 13), an instruction to each SLB device (22, 32) to set detection parameters, the detection parameters comprising at least a detection method, wherein each SLB device is to: perform an initialization configuration based on the detection parameters, and detect the results of performance of the servers in a data center at which the SLB device is located according to the detection parameters; and sending periodically, by the GLB device (11, 12, 13), a request to each SLB device (22, 32) in turn to obtain the detection results of performance of the servers sending, by the GLB device (11, 12, 13), an instruction to each SLB device (22, 32) to set detection parameters, the detection parameters comprising at least a detection method, wherein each SLB device is to: perform an initialization configuration based on the detection parameters, and detect the results of performance of the servers in a data center at which the SLB device is located according to the detection parameters; and perform an initialization configuration based on the detection parameters, and detect the results of performance of the servers in a data center at which the SLB device is located according to the detection parameters; and sending periodically, by the GLB device (11, 12, 13), a request to each SLB device (22, 32) in turn to obtain the detection results of performance of the servers