The present invention provides a multichannel label-free biosensing fiber-optic system, which comprises one or more light sources coupled into optical fibers, one or more optical fiber circuits for performing coupling or/and directional transmission of optical-fiber guided lightwaves, one or more optical-fiber-input and optical-fiber-output optical switches, a plurality of optical fibers provided with label-free optical sensing elements working in the reflection manner on the optical fiber ends, and the light detection parts, wherein the optical-fiber-input and optical-fiber-output optical switch is provided with a plurality of outputs and/or a plurality of inputs, and with the plurality of outputs and/or plurality of inputs, by the switching function, the reflected light from the label-free optical sensing elements working in the reflection manner on the designated optical fiber ends is received by the light detection part, so that multichannel sensing is realized.