The invention discloses a novel flow velocity and flow direction automatic measuring instrument and a measuring method thereof. The flow velocity and flow direction automatic measuring instrument comprises a fixing platform, a hollow steel tube, an area array CCD (charge coupled device) and an open and close door, wherein the hollow steel tube is connected with the fixing platform, an injection agent mouth is arranged at the top of the hollow steel tube, the open and close door is arranged at the tail of the hollow steel tube, the open and close door is connected with an electromagnet, the area array CCD is fixedly connected onto the hollow steel tube, the area array CCD collects images, and sends the images to a processor, the processor is located on the fixing platform, and a fixing plate and a movable pin are arranged below the fixing platform. The measuring method of the flow velocity and flow direction automatic measuring instrument includes: collecting two different frames of the images of trace dye at different moments through the area array CCD; processing the images so as to obtain the flow velocity and the flow direction. The flow velocity and flow direction automatic measuring instrument is ingenious in structure and low in cost. The measuring method of the flow velocity and flow direction automatic measuring instrument is small in random error, high in automatic degree, and simple and easy to implement, and substantially improves measurement accuracy of a flow velocity vector.