The invention provides a high-efficiency powder-selecting machine with wide particle diameter distribution. The powder-selecting machine comprises a shell body, a cage-type rotor, a feed spreading tray, a central wind pipe and a coarse powder cone; the central wind pipe is arranged on the upper part of the shell body; the lower part of the shell body is provided with the feed spreading tray and the rotor; a wind inlet and a feed inlet are arranged on the shell body; the lower part of the rotor is provided with the coarse powder cone; a semiannular collecting hopper of a secondary sorting device is arranged on the upper part of the coarse powder cone; a lower mouth of the collecting hopper is communicated with an upper mouth of a four-way joint through a wind locking valve; two side mouths of the four-way joint are connected with a separator and secondary wind respectively; a lower mouth of the four-way joint is connected with the wind locking valve; an upper mouth of the separator is connected with a wind outlet pipe; and a lower mouth of the separator is communicated with an overflow valve through the wind locking valve. The high-efficiency powder-selecting machine can once sort out fine powder, finer powder and coarser powder needed by cement with wide particle diameter distribution, and improve the particle distribution of a sorted powder body so that water amount needed by the cement is reduced, improve the compatibility between the cement and an additive and the working performance of the cement and reduce energy consumption and production cost.