G.654.E fiber is used in the transmission system, because of the large cut-off wavelength and the coupling method with the transceiver end equipment, multi-path interference(MPI) may occur, which will affect the transmission performance. In order to explore the influencing factors of MPI, this paper analyzes the effects of fiber type, fiber length, looped condition, connection mode and the tail fiber type on the MPI through the narrow-band external cavity laser/optical power meter method in 1310 nm light source wavelength. The experiment results show that, for short-distance links, it is possible to reduce MPI by means of circular filtering and hot-splicing instead of active connectors, for long-distance links, try to avoid mixed connections of different types of optical fibers.