Abstract: In order to improve spectrum efficiency of communication system, a novel two-dimension Time- frequency Overlapped Multiplex System is proposed, and based on this communication system, a rapid detection algorithm is studied. The experimental results show that compared with the traditional maximum likelihood sequence estimation detection algorithm, the proposed algorithm obtains significant increase in detection speed at the expense of some performance of bit err ratio, so as to promote practical process of the two-dimension Time- frequency Overlapped Multiplex System. Its performance at a high signal to noise ratio is still better than that of the QAM modulation with the same spectrum efficiency. This shows that improving the transmission rate with overlapped signals can achieve greater gains than that of using high-level QAM modulation with the same spectrum efficiency.