The invention discloses a constant temperature-constant humidity laboratory, which belongs to the field of laboratories. A workshop, an equipment room, an air feeding bin and an air mixing bin are arranged in the laboratory, the top of the workshop is provided with a porous plate suspended ceiling, an air feeding pipe is arranged in the air feeding bin, a fresh air hole introduces fresh air into the air mixing bin by a fresh air pipeline, an air conditioner unit is arranged in the equipment room, the lower part of the air mixing bin is connected to the air conditioner unit, the air conditioner unit is connected to the air feeding pipe by an air conditioner auxiliary electric heater, a plenum chamber and a humidifier, air returning upright columns are arranged in the workshop, the lower parts of the air returning upright columns are provided with air returning holes, and the air returning upright columns are connected to the air mixing bin by air returning pipelines. The constant temperature-constant humidity laboratory also comprises an intelligent control system having a PLC. Compared with the prior art, the constant temperature-constant humidity laboratory has the characteristics of high airflow circulation strength, stable wind speed, uniform temperature and humidity, no dust accumulation, good stability, capability of meeting a fresh air volume demand of workers, high disturbance resistance, high control precision and direct and visible temperature and humidity changes in the laboratory.