The present invention provides a chromaticity adjustment method, a chromaticity adjustment device, and a display panel. The chromaticity adjustment method makes a chromaticity of a white image conform to a target value by adjusting a thickness of a liquid crystal layer corresponding to blue pixels. Therefore, a chromaticity deviation in the display panel can be relieved. In addition, after adjusting a thickness of a blue photoresist layer, an adjustment range of a gray scale of blue sub-pixels (B) can be reduced. While improving the chromaticity, an impact on light transmittance rate can also be reduced, and color interference can be prevented.