A purification device of baby carriage is provided and includes a main body, a purification unit, a gas guider and a gas detection module. The purification unit, the gas guider and the gas detection module are disposed in the main body to guide the gas outside the main body through the purification unit for filtering and purifying the gas, and discharge a purified gas. The gas detection module detects particle concentration of suspended particles contained in the purified gas. The gas guider is controlled to operate and export a gas at an airflow rate within 3 minutes. The particle concentration of the suspended particles contained in the purified gas, which is filtered by the purification unit, is reduced to and less than 0.75 μg/m3. Consequently, the purified gas is filtered, and the baby inside the baby carriage can breathe with safety.