The invention relates to a random distribution control experiment device and method for powder particle size of a pan mill system, and belongs to the technical field of distributive control. The experiment device comprises a spiral feeding control device, a mill rotating speed adjusting device, a milling pan clearance servo control device, a sampling device, a laser particle analyzer, a control cabinet and a host computer. The control method of the experiment device comprises the steps of 1) primarily setting; 2) starting the pan mill system; 3) sampling through the sampling device; 4) detecting the PDF shape of actual powder particle size distribution through the laser particle analyzer; and 5) updating the primary setting by a random distribution control algorithm. According to the experiment device and the control method, a series of random distribution control algorithms can be verified, so that a good experiment platform is supplied for teaching and science research; the non-Gaussian distribution shape of output random variable of a random distribution system can be effectively controlled, and moreover, the average value and the variance of the output random variable can alsobe effectively controlled.