The present invention provides a partition plate throat width measuring chain bead for a steam turbine, and the measuring chain bead comprises at least more than two global probe heads (1), at least more than two positioning sticks (2) and a measuring device body (3). The global probe heads (1), according to different diameters from small to big or from big to small, each adjacent global probe head (1) of which the center is positioned in the same plane, according to same or different spaces, are arranged in sequence to form a measuring chain, the global probe heads (1) are arranged on the positioning sticks (2) and fixed on the measuring device body (3) through the positioning sticks (2) according to an arrangement way of the global probe head (1). The measuring device is characterized in that the measuring size range is large, the operation is simple, the measuring accuracy is high, and the reading is direct-viewing, flexible and convenient.