A low complexity noncoherent maximum likelihood multireader detection algorithm for active radio frequency identification (RFID) test system using fast frequency hopping pattern was proposed. Firstly, the timefrequency (TF) matrix pattern of every reader was calculated based on expectation element selection mode. By means of exploiting the majority row of TF matrix of the desired reader was used for predetection. Then these data was remapping and coding. Finally it used subspace maximum likelihood detection algorithm to recover the reader signal. The algorithm complexity and performance achieved a good compromise with good practical value. Computer simulation verified the validity of the proposed algorithm.