The invention relates to a current velocity and current direction testing device and a method for testing the current velocity and the current direction simultaneously. The invention comprises an impeller flow testing sensor, and the invention is characterized in that the invention also comprises another impeller flow testing sensor which is connected with the invention, and central axial cords of two impeller flow testing sensors are crossed mutually into integrity. Adial dimensions of the two impeller flow testing sensors are same or different. The testing method of the invention comprises firstly, putting a device which is produced after the two impeller flow testing sensors are crossed mutually into integrity into a flow field to obtain respectively two velocity vectors which are crossed mutually, then, compounding the velocity vectors according to a data collecting and processing device, and calculating or displaying an actual velocity and a comparative current direction. The actual current direction can be combined easily through combining an electric compass. The invention is the testing device with miniaturization and low cost, and the invention has reasonable structure, simple use, and can test the current velocity and the current direction simultaneously, and increase intelligence and economy of the flow testing sensors.