Aiming at the problems of low thermal efficiency, unstable temperature and difficult guarantee of tea quality of tea dryer, the coal-fired hot air-drying furnace was studied in order to find an effective constant temperature control method. An improved particle swarm optimization (IPSO) algorithm was proposed by chaotic processing of particle swarm optimization (PSO). Then the parameters of fuzzy PID controller were optimized by IPSO to overcome the shortcomings of PSO, including premature, low optimization efficiency and real-time on-line adjustment of PID parameters. According to the real-time temperature of the hot blast stove, the amount of smoke discharged from the hot blast stove could be adjusted automatically to realize the constant temperature of the dryer. Moreover, the optimized fuzzy PID control strategy was used to simulate and test the system. The results showed that the method used in this study could effectively control the amount of smoke exhausted from the hot-blast stove according to the temperature of the dryer, so as to control the temperature of the hot-blast in real time and achieve the goal of constant temperature control. This method solved the traditional issues in controlling the temperature and reducing the energy consumption, and improved the thermal efficiency of the dryer and resulted in the guarantee of the good tea quality.