The present invention relates to a device and a method for measuring a water level using a correlation coefficient analysis and more specifically, to a device and a method for measuring a water level using a correlation coefficient analysis capable of reducing water surface detection errors of liquid and improving the accuracy in the water surface detection of the liquid when a camera is shaken. The device for measuring a water level comprises: a watermark installed in the liquid; an image acquisition part for acquiring images containing the watermark and the water surface of the liquid with a time difference; and a water level recognition part having a main control part. The main control part performs a gray scale image process after selecting two images among the images and extracts each inspection section for water level detection from the two gray scale images. Then, the main control part calculates and analyzes a correlation coefficient of the inspection sections for water surface detection to detect the water surface of the liquid and determines the water level of the liquid from the detected water surface of the liquid. [Reference numerals] (AA) No; (BB) Yes; (S10) Select images; (S20) Perform a gray scale image process; (S30) Set inspection sections; (S40) Is the images shaken?; (S50) Revise the shaking of the images; (S60) Statistical filtering process; (S70) Calculate a correlation coefficient; (S80) Detect a water surface; (S90) Determine a water level