The mid-infrared (MIR) and far-infrared (FIR) oscillators in the IRFEL facility share a common beamline, which is designed to deliver output laser radiation to multiple experimental stations while enabling real-time, online diagnostics of laser parameters via the integrated laser diagnostic system. The beamline primarily comprises the following components: a front-end cavity with diamond isolation windows, gold-coated mirrors equipped with mirror chamber adjustment mechanisms, vacuum beamline components, and a laser diagnostic system. With a total beamline length of 33.99 m, the system incorporates 13 mirror chambers. The vacuum level is maintained below 10⁻⁴ Pa, and the overall transmission efficiency exceeds 50%.