The utility model discloses a drilling fluid semipermeable membrane evaluation device, and overcomes the shortcoming that an existing drilling fluid semipermeable membrane evaluation device is relatively low in accuracy. The drilling fluid semipermeable membrane evaluation device comprises a four-way valve, an upstream piston container, a core holding unit and a downstream piston container, wherein two ends of the upstream piston container are respectively communicated with the four-way valve and an upstream workshop of the core holding unit, two ends of the downstream piston container are respectively communicated with the four-way valve and a downstream workshop of the core holding unit, and the four-way valve is connected with a rubber sleeve of the core holding unit. A pipeline, between the upstream piston container and the upstream workshop of the core holding unit, is provided with a first pressure sensor; a second valve is arranged between the downstream workshop of the core holding unit and the downstream piston container; and the second valve is provided with a second pressure sensor or a pipeline, between the downstream workshop of the core holding unit and the second valve, is provided with the second pressure sensor. The drilling fluid semipermeable membrane evaluation device solves the problem of evaluation of mud shale membrane efficiency.