The invention relates to a test device and a method for simulating acid etching crack flow guide capability. The test device consists of a liquid storage tank, a diaphragm pump, a pipeline electric heating sleeve, a flow meter, a flat plate clamping device, a pressure return valve, a condensing pipe, a waste liquid tank, a data collection and control panel and the like, wherein the inner side of the clamping device is provided with a temperature sensor and a pressure sensor, both ends of the lamping device are provided with small liquid inlet holes and small liquid outlet holes, the inside of the clamping device is provided with a liquid inlet piston and a liquid outlet piston, a rock core chamber is arranged between the liquid inlet piston and the liquid outlet piston, the clamping device is connected with a pressure machine, and the diaphragm pump, the pipeline electric heating sleeve, the flow meter, the temperature sensor and the pressure sensor are all connected with the data collection and control panel and a computer. The test method comprises the following steps; cutting the rock into rock core samples conforming to the standard flow guide chamber, and sealing and curing the rock core samples; placing the rock core samples into the rock core chamber; adopting a gasket for simulating the crack width; sequentially opening a clear water storage tank and an acid liquid storage tank; starting the computer, and inputting experiment parameters; and calculating the flow guide capability of the acid etching cracks of the rock core samples. The invention can simulate the real conditions of the underground acid etching crack forms, and can meet the requirements of the acid etching crack flow guide capability test under different environment conditions.