Detecting device and method, and liquid crystal dropping apparatus and method are provided. The detecting device is configured to detect a volume of an uneven region of a color filter substrate in a display area, and includes at least one collection unit and a processing circuit. The collection unit is configured to obtain a surface image of the color filter substrate in the display area, and output the obtained surface image to the processing circuit. The processing circuit is connected to the collection unit and configured to process the surface image to obtain a volume of the uneven region of the color filter substrate in the display area. The detecting device and the corresponding method can automatically obtain the volume of the uneven region of the color filter substrate in the display area, thereby obtaining an appropriate filling amount of liquid crystal and ensuring product quality.