The invention belongs to the technical field of marine organism tests and anti-fouling materials, and relates to a flow channel type marine organism adhesion testing device which is used for simulating the flowing state on the surface of a ship body, testing the adhesion of marine fouling organisms on the material surface and researching the effect of different flowing speed and environment conditions on the adhesion of marine fouling organisms. A water inlet, an stainless steel plate with openings, a honeycomb-shaped polycarbonate sheet, a stainless steel sieve plate and an exhaust valve are respectively manufactured on the upper side in a settling chamber of a box structure from right to left, a test cavity is manufactured at the left end of the settling chamber transversely, a differential pressure transformer is manufactured on the side edge at left end of the test cavity, a vacuum pump is arranged in the test cavity, a water tank is arranged at the left side end of the test cavity, a light source is manufactured at the top of the water tank, an outlet pipeline at the bottom part of the water tank is communicated with the water inlet under the control of a multi-end valve, and a frequency conversion pump, a flow meter and a pressure transmitter are respectively manufactured in the communicated pipeline sequentially; the structure is simple, the usage and operation are convenient and the data test is accurate, thereby being convenient for application and popularization.