A unified communications UC-based video conference subsystem, comprising a video conference terminal, VCT, that incorporates a video processing module and a call control module and is connected to a network, wherein the call control module is connected to the video processing module, wherein the subsystem further comprises a PC host, a UC client, and a user input device; the UC client is installed on the PC host, the PC host is connected to the network, the VCT is connected to the PC host, the UC client incorporates a VCT application module and a UC-VCT communications module, and the VCT incorporates a VCT-UC communications module; the VCT application module is configured to receive a request sent by a calling user for querying call information of a called VCT, send the query request to a UC server, receive the call information of the called VCT that is returned by the UC server, and send the call information of the called VCT to the UC-VCT communications module; and is further configured to receive an incoming video conference call message that comprises an incoming call number, send a calling party information query request that comprises the incoming video conference call message to the UC server, receive calling party information of the video conference call, wherein the calling party information is queried and obtained by the UC server according to the incoming call number, output the calling party information of the video conference call in a visual manner, receive a call answer or reject request input by a user, and send the request to the UC-VCT communications module; the UC-VCT communications module is configured to establish a communication channel between the UC client and the VCT, receive the call information of the called VCT, and send the call information of the called VCT to the VCT-UC communications module of the VCT; and is further configured to receive the call answer or reject request, and send the call answer or reject request to the VCT-UC communications module; the VCT-UC communications module is connected to the call control module, and is configured to receive the call information of the called VCT sent by the UC-VCT communications module, and send the call information of the called VCT to the call control module; and is further configured to receive the incoming video conference call message that comprises the incoming call number, send the incoming video conference call message to the VCT application module by using the UC-VCT communications module, receive the call answer or reject request, and send the call answer or reject request to the call control module; the call control module of the VCT is configured to receive the call information of the called VCT, and initiate a video conference call to the called VCT according to the call information of the called VCT; and is further configured to receive the call answer or reject request, and perform an operation of answering or rejecting the incoming call; and the user input device is connected to the PC host, and is configured to receive the request sent by the calling user for querying the call information of the called VCT, and send the query request to the VCT application module, characterized in that the PC host further comprises: a user input device control module, configured to implement switching, between the PC host and the VCT, of control rights on the user input device.