Quorum sensing is a mechanism used by single-cell bacteria to monitor their population density and control a variety of physiological functions in a cell-density-dependent manner. We constructed an 5’ mrtI-lacZ (the mrtI is the AHL production gene in M.tianshanesne) transcriptional fusion strains. We found the supernatant of three strains which were got from pea and one strain which got from clover can induce the mrtI-lacZ expression. We also found the more the supernatant was the stronger the lacZ expressed. The TLC experiment showed that their AIs maybe have the same structure. This study showed the interaction between strains with same function and also paved the way of further studying the relationship between quorum sensing and symbiotic nitrogen fixation of the M. tianshanesne strains.