The invention provides an observation device for a water gauge of a ship. The observation device comprises a transparent pipe, wherein a curve-shaped wave resistant pipe is connected to the tail part of the transparent pipe, and the diameter of the curve-shaped wave resistant pipe is smaller than that of the transparent pipe; an electromagnet, a camcorder lens and magnifying glass are sequentially arranged at the upper part of the transparent pipe from top to bottom, the electromagnet is electrified through a power supply device on the ship, and the camcorder lens is connected with an image display system on the ship. Through the adoption of the observation device disclosed by the invention, a measurer does not need to go down to the water surface, so that the draught depth of the ship can also be observed, interference of waves on the water surface is avoided, the safety of observing the draught situation of the ship is greatly improved, and besides the accuracy of reading the water gauge is improved.