The invention discloses an experimental device for detecting PM2.5 of solid combustible, and belongs to the technical field of experiment equipment. The device comprises a reaction device, wherein a reaction cover is arranged at the upper end of the reaction device; a support is arranged at the lower end of the reaction device; an air inlet is formed in the lower side of the reaction device, and an air inlet pipe is arranged at the tail end of the air inlet; a reaction plate, a heat insulation plate and a dust collection plate are sequentially arranged in the reaction device from top to bottom; a circular hole is formed in one side of the reaction cover; a connecting port is formed in the round hole; a connecting pipe is arranged at the connecting port; a water tank is arranged at the endpart of the connecting pipe; a condensation pipe is arranged in the water tank, a PM2.5 detection terminal is arranged on one side of the water tank, and an exhaust pipe is arranged at the end of thePM2.5 detection terminal. The device is simple and convenient to use, high in practicability and convenient to popularize and use. The invention solves the problems that when flammable substances areadded into a traditional solid combustion substance device to assist combustion of solid combustion substances, time and labor are wasted during fire generation, the environment is polluted, and experimental collection and detection of PM2.5 generated by solid combustion substance research in a laboratory cannot be satisfied.