Abstract: An experimental apparatus and its teaching mode was designed for simultaneously visualizing the flow and the spray of gaseous fire suppressants, whose flow was complex and invisible. With electrical capacitance tomography and laser shadowgraphy, the flow pattern in the pipe and the structure of the spray out of the nozzle was visualized. Meanwhile, details of the temperature and pressure in the discharging system were acquired synchronously by the sensors with high sampling frequency. Experimental teaching was carried out based on the apparatus, in which the students could observe directly the discharging process of fire suppressants, master the measurement methods of the related key parameters and develop interdisciplinary concepts and innovative spirits.