The invention discloses a cable stratum tester, which comprises a probe and pressure testing module, a sampling tube module, a hydraulic power module, a pump drainage module, an electronic control module, an underground fluid identification module and a public pipeline which penetrates through each module. A sampling tube of the sampling tube module comprises a fluid storage tube for accommodating own fluid and a pressure-volume-temperature (PVT) sampling tube for accommodating the fluid of a tested stratum. The underground fluid identification module can detect the quality characteristics of the stratum fluid entering a sample pipeline in real time. The pump discharge module has three operating modes, namely a pre-test mode, a fluid pump drainage mode and a fluid back-injection mode. Compared with the conventional cable stratum tester, the cable stratum tester has the advantages that: a high-quality original stratum fluid sample can be obtained; and the obtained stratum fluid sample is analyzed, and then various characteristic parameters of the stratum fluid can be accurately obtained. The cable stratum tester adopts a modular structural design, so that the using flexibility of the tester is improved, and the tester is convenient to assemble and maintain.