A purification device of exercise environment is provided and includes a main body, a purification unit, a gas guider and a gas detection module. The main body has at least one gas inlet and at least one gas outlet. The purification unit, the gas guider and the gas detection module are disposed in the main body. The purification unit filters a gas in an exercise environment introduced through the at least one gas inlet. The gas guider operates continuously to transport the gas in the exercise environment to be introduced through the at least one gas inlet and to flow through the purification unit. The gas detection module detects a gas information and a particulate cleanliness of the air in the exercise environment, and the particulate cleanliness of the gas in the breathing region around the nose of the exerciser reaches 0˜20 μg/m3 accordingly.