It is suitable for the sampling of liquid medium, gravity sampling and heating/cooling type. The medium is first purged by the coupling valve, and then the temperature is controlled to a suitable range by the heating/cooling jacket. The medium in the sample chamber flows under the action of gravity. In the sampling bottle, the coupling valve has the function of quantification and simultaneous control of multiple valves, making the sampling process more accurate and safer for the operator, and the process pressure is separated from the sampling pressure, and the system can be used for higher pressure sampling conditions