The invention relates to a sampling device for sampling fluid in a container and a use method thereof. The sampling device includes a body, a first valve and a second valve; the body is provided with a fluid channel and a sampling chamber communicating with the container through the fluid channel and used for containing the fluid, wherein the sampling chamber is provided with a sampling port; the first valve and the second valve are arranged at the fluid channel at intervals, and are configured for selectively turning on one of the two valves. The amount of the fluid entering the sampling device is reduced, so as to reduce the waste of the fluid during sampling, and reduce the disturbance to the fluid in the container as far as possible. The sampling device has the advantages of simple structure, small size, light weight, high pressure resistance and low cost.