Abstract: Based on the statistical characteristics of frame synchronization metric function and the probability of correct frame synchronization theoretical calculation method, this paper proposes a threshold selection criterion of frame synchronization for distributed multiple input multiple output-orthogonal frequency division multiplexing (MIMO-OFDM) system. By this criterion, receiver would achieve perfect frame synchronization theoretically. Moreover, a simplified criterion is presented based on the 3σ principle of normal distribution. By systematically analyzing and calculating, some valuable conclusions are obtained as following: Firstly, any required performance of correct frame synchronization can be satisfied with the proposed threshold selection criterion above a specified signal noise ratio(SNR). Secondly, KG*4The KG*4calculation of proposed simplified criterion is very small and the probability of correct frame synchronization can achieve 99.87%. Finally, the frame synchronization metric value decreases with the increase of transmitting antennas, and the frame synchronization algorithms need to be improved correspondingly. At the last, the proposed threshold selection criterion is proved to be accurate and valid by Monte-Carlo simulation in the different systems with different MIMO transmitting antenna numbers and the specified SNRs.