The invention provides a multi-user measurement equipment unrelated QKD system and method based on a GHZ entangled state. The multi-user measurement equipment unrelated QKD system comprises N + 1 senders and N measurement parties, wherein the first sender, the second sender,..., and the Nth sender are connected with each other through a classical channel, the Nth sender and the Nth measurer are connected one by one through quantum channels, and the (N + 1)th sender is connected with the first measurer, the second measurer,..., and the Nth measurer through quantum channels. And the first sender, the second sender,..., and the Nth sender send the single photon polarization state, and the (N + 1)th sender sends the GHZ entangled state. Particles prepared by the first, second,..., Nth and (N +1)th sending parties interfere with each other in the first, second,..., Nth measuring parties, Bell state measurement is carried out, and a code value is formed. According to the invention, the communication distance is greatly increased, the attack on the measurement equipment can be resisted, and the first, second,..., and Nth measurement parties in the invention can be non-trusted parties.