A method for implementing a Voice over Internet Protocol, VOIP, call in a cloud computing environment, characterized in that, the method comprising: receiving, by a cloud desktop virtual machine, a VOIP call request message from a Remote Desktop Protocol, RDP, client included in a cloud desktop client or from a communication peer end, wherein the cloud desktop virtual machine is located in a cloud computing server in a data center, the cloud desktop client corresponds to the cloud desktop virtual machine, and an RDP proxy is used to connect the cloud desktop client to a Wide Area Network, WAN, between the cloud desktop client and the data center, so that the cloud desktop client gains access to the cloud desktop virtual machine in the cloud computing server, wherein the RDP proxy is set in an access router or an access switch located at an edge of an enterprise network in which the cloud desktop client is located; sending, by the cloud desktop virtual machine, a session setup request message to the RDP proxy according to the VOIP call request message; receiving, by the cloud desktop virtual machine, a session setup response message sent by the RDP proxy, wherein the session setup response message comprises voice session media information of the RDP proxy, the voice session media information of the RDP proxy includes an Internet Protocol, IP, address and a port number of the RDP proxy; and sending, by the cloud desktop virtual machine, the voice session media information of the RDP proxy to the communication peer end, so that the communication peer end performs, according to the voice session media information of the RDP proxy, a VOIP call with the RDP client by using the RDP proxy. receiving, by a cloud desktop virtual machine, a VOIP call request message from a Remote Desktop Protocol, RDP, client included in a cloud desktop client or from a communication peer end, wherein the cloud desktop virtual machine is located in a cloud computing server in a data center, the cloud desktop client corresponds to the cloud desktop virtual machine, and an RDP proxy is used to connect the cloud desktop client to a Wide Area Network, WAN, between the cloud desktop client and the data center, so that the cloud desktop client gains access to the cloud desktop virtual machine in the cloud computing server, wherein the RDP proxy is set in an access router or an access switch located at an edge of an enterprise network in which the cloud desktop client is located; sending, by the cloud desktop virtual machine, a session setup request message to the RDP proxy according to the VOIP call request message; receiving, by the cloud desktop virtual machine, a session setup response message sent by the RDP proxy, wherein the session setup response message comprises voice session media information of the RDP proxy, the voice session media information of the RDP proxy includes an Internet Protocol, IP, address and a port number of the RDP proxy; and sending, by the cloud desktop virtual machine, the voice session media information of the RDP proxy to the communication peer end, so that the communication peer end performs, according to the voice session media information of the RDP proxy, a VOIP call with the RDP client by using the RDP proxy.