The invention relates to a throttling device pressure tapping machine for measuring moisture flow. The machine is suitable for measuring the moisture flow in a vertical pipe, and comprises a pressuretapping machine casing which covers a pressure tapping portion of the throttling device and a built-in pressure guiding pipe, uniformly distributed pressure tapping grooves or porous radial pressure tapping ports are formed in a circle of the lower portion, near the pressure tapping machine casing, of the pressure tapping portion, an annular pressure guiding passage is formed between the throttling device at the pressure tapping portion and the pressure tapping machine casing, and the pressure tapping grooves or the pressure tapping ports make a medium passage be communicated with the annularpressure guiding passage in the throttling device; the built-in pressure guiding pipe communicated with the annular pressure guiding passage is arranged in the pressure tapping machine casing. The machine can prevent the pressure guiding pipe from being blocked by liquid and generating a liquid column, thereby ensuring reliable measurement of pressure and differential pressure.