The invention discloses a tin-based spherical welding powder production pneumatic conveying device for an SMT. The tin-based spherical welding powder production pneumatic conveying device comprises a centrifugal atomizing chamber. The lower portion of the centrifugal atomizing chamber is provided with a cyclone conveyer. The cyclone conveyer is connected with the lower portion of the centrifugal atomizing chamber through a feeding opening in the upper end of the cyclone conveyer. The side face of the cyclone conveyer is provided with an air inlet. The upper portion of the cyclone conveyer is further provided with a discharging opening. The air outlet end of a centrifugal blower is divided into two paths. One path is sequentially connected with an air inlet of a cooler and an air inlet of the cyclone conveyer through a pipe. The other path is communicated with the upper portion of a coarse powder collection chamber through a pipe. A grading impeller is arranged at the top of the coarse powder collection chamber. The discharging opening of the cyclone conveyer is connected with the side face of the grading impeller through a pipe. The output end of the grading impeller is communicated with a fine powder collection chamber through a pipe. The fine powder collection chamber is provided with an air outlet connected with the air inlet end of the centrifugal blower. The tin-based spherical welding powder production pneumatic conveying device solves the problems that in the welding powder production process, dust effusion is generated in the dust carrying process, and the structure property of centrifugal atomizing powder is changed due to the fact that the temperature of the centrifugal atomizing powder rises in a transfer cylinder.