A wireless communication device configured to operate with a first wireless communication protocol and a second wireless communication protocol and a method for performing coexistence control based on adaptive threshold adjustment in the wireless communication device are provided. The method may include: performing wireless communication operations with the first wireless communication protocol and the second wireless communication protocol concurrently; comparing a current throughput with a throughput threshold; in response to the current throughput being less than the throughput threshold, comparing a received signal strength indicator (RSSI), in communication using the second wireless communication protocol, with a signal strength threshold to generate at least one comparison result; and selectively sending a null frame according to the at least one comparison result, in order to temporarily avoid communication using the second wireless communication protocol.