— In order to extend the coverage of wireless communication to metropolitan scale, the Worldwide Interoperability for Microwave Access (WiMAX) standard was developed and ratified as the IEEE 802.16d standard in June 2004. The standard defines an adaptive modulation framework which allows a WiMAX system to communicate with various burst profiles according to the link quality. The selection mechanism of a suitable burst profile is left open for research. In this paper, we devised a novel link adaptation algorithm with dynamic threshold probing based on an extension of our previous work on a MIMO-based WiMAX systems simulation framework. Our algorithm was capable of quickly adapting to channel conditions using PHY layer metrics and MAC layer statistics. Evaluation showed that our algorithm could achieve high system throughput while minimizing the packet drop rate significantly.