The invention relates to a turbine blade root fatigue test simulator with a cooling channel, and a test method, and belongs to the technical field of the turbine blade root test. Turbine blade roots are symmetrically arranged at two ends of a connecting piece to form a test piece main body, the cooling channel is arranged at a vertical central line location in the test piece main body; simulationcooling channels are formed on the front side and the back side of the test piece main body; the connecting piece, the turbine blade roots, the cooling channel and the simulation cooling channels arein one-piece casting; the cross section of the cooling channel is rectangle, the longitudinal section of the cooling channel comprises a port rectangle section, a trapezoid section and a middle rectangle section which are in connection. The fatigue test simulator disclosed by the invention solves the influence on the turbine blade fatigue life by the cooling channel, the accuracy of the fatigue test is guaranteed when the test cost is reduced. The centrifugal force of the turbine blade root is replaced through the tension force of a fatigue tensile machine, and the fatigue test can be conveniently and accurately accomplished.