It has been widely noted that the traditional test equipments cannot catch up with the increasing speed, pin count, and parameter accuracy of advanced IC products, rapidly increasing the test cost for semiconductor chips and wafers. To solve this problem, we had proposed a novel wireless test system called HOY. In this paper we present a stable performance MAC Protocol for the HOY wireless tester under large population. It provides three functions: Test Initialization (TI), NACK Based Reliable Multicast (NBRM), and Polling. The tester may use TI to gather information from the dies under tests (DUTs) and apply NBRM to transmit test commands to the DUTs. Upon finishing the test process, the HOY tester collects the test results by Polling. The stable performance indices include the throughput and average performance TI, and the reliability and transmission time of NBRM. We show that the number of DUTs has little effect on performance, making the improvement of test parallelism promising for the HOY approach.