The invention provides a determination device and method for a layered steam distributing valve. The determination device comprises an outer sleeve, a valve base, a main pipe and a bypass branch pipe;the valve base is located in the outer sleeve, the upper end of the valve base is in sealing connection with a sleeve opening of the outer sleeve, a through runner is formed in the valve base in theaxial direction, an axial insertion groove allowing the layered steam distributing valve to be inserted is formed in the side adjacent to the runner, an upper connector is connected into the upper endopening of the runner of the valve base in an inserted mode, the upper end of the axial insertion groove is communicated with an inner cavity of the outer sleeve, and the lower end of the axial insertion groove is communicated with the runner; the main pipe is arranged at the sleeve bottom of the outer sleeve in the axial direction, and the upper end of the main pipe is connected to the lower endopening in an inserted mode; the bypass branch pipe is close to the lower end of the outer sleeve, connected to the side wall of the outer sleeve in an inserted mode in the radial direction, and communicated with an inner cavity of the outer sleeve. Accordingly, the corresponding relationship of the steam injection capacity and the steam injection flow of the layered steam distributing valve canbe tested, and the determination device and method have the advantages of being simple in detection mode, reliable and accurate.