The invention discloses a gas filtration module and a projecting device. The gas filtration module is used for a projecting module and covers an airflow port of the projecting module. The gas filtration module comprises a filtration element and a cleaning unit. The cleaning unit covers the airflow port. The cleaning unit drives the filtration element to move according to a cleaning starting signal, so that dust on the filtration element is cleaned. Further provided is a projecting device. The gas filtration module is used for the projecting device, so that usage convenience is improved.