A device for measuring a mass flow rate of a multiphase flow based on ray coincidence measurement includes a support frame and a plurality of ray detection assemblies. The support frame includes a central through hole and an outer wall, and the central through hole is configured to receive a fluid pipe. The plurality of ray detection assemblies is distributed along the circumferential direction of the outer wall and is perpendicular to the axis of the central through hole. The plurality of ray detection assemblies each includes a scintillation crystal and a detector, and the scintillation crystal is disposed between the outer wall and the detector.