The invention discloses an optical fiber eigenmode multiplexing communication method and system. The method comprises the following steps: directly taking optical fiber eigenmode as an information carrier, and then performing low-crosstalk multiplexing transmission on multiple optical fiber eigenmodes in the eigenmode separated multi-model optical fiber. The system comprises a transmitting end, a multichannel eigenmode multiplexer, the eigenmode separated multimode optical fiber, the eigenmode separated optical amplifier, a multichannel eigenmode de-multiplexer and a receiving end; the effective refractive index difference between the multichannel optical fiber eigenmodes supported by the eigenmode separated multimode optical fiber is large and the crosstalk is low; the multichannel eigenmode multiplexer realizes the conversion and the multiplexing to the optical fiber eigenmode from the multichannel Gaussian mode; the multichannel eigenmode multiplexer realizes the conversion and de-multiplexing to the Gaussian mode from the multichannel optical fiber eigenmode; the multiplexing and the de-multiplexing are extensible and provide the single mode optical fiber interface. The optical fiber eigenmode multiplexing communication method disclosed by the invention supports the low-crosstalk multiplexing communication of the multichannel optical fiber eigenmode, the multi-in and multi-out digital signal processing is unnecessary, the single model optical fiber is compatible, and the communication capacity and the spectrum efficiency can be effectively improved.