The invention belongs to the field of a moisture gas-liquid two-phase flow measuring technology and relates to a moisture two-phase flow measuring device with an annular chamber gas-liquid separation pressure measuring device, comprising a measuring pipeline, wherein a pipe wall of each pressure measuring position of the measuring pipeline, which is located on the same plane vertical with a axis, is provided with four inner pressure measuring holes; the two of the four inner pressure measuring holes are formed at the maximum diameter position in a horizontal direction of the pipe wall, and the other two of the four inner pressure measuring holes are formed at the maximum diameter position in a vertical direction of the pipe wall; an annular chamber structure is fixedly arranged on the peripheries of the four inner pressure measuring holes; the annular chamber and a measuring pipeline body are coaxial and are fixedly arranged on the outer wall of each pressure measuring position of the measuring pipeline body so as to form a gas-liquid separation chamber with a certain capacity space; a pressure leading opening which is abutted with an outer pressure leading pipe is formed above the vertical axis of the chamber; and a dirt discharging opening which is abutted with an outer dirt discharging pipe is formed below the vertical axis of the chamber. The moisture two-phase flow measuring device has the advantages that the structure is simple, the dependence on a large-sized gas-liquid separator is free, pressure measuring precision is high, pressure measurement is not influenced by a liquid phase, and the implementation is convenient.