A multi-functional air circulation system includes a bottom base, a flow-splitting base, a filter and a main engine. The bottom base has a lower flow-guiding surface, a net, and a space used to contain diverse improving agents. The flow-splitting base is fixed on the bottom base, including an inner flow-guiding surface to rush air flow generated by a blade member down to the bottom base. The filter is laid at an exit of the inner flow-guiding surface, composed of two filter bases forming a room between them for containing aromatic powder, etc. The main engine includes a motor having its shaft fixed with a blade member, and a control system. The motor is installed in a rear shell combined with a front shell. Air is sucked in through the rear shell to run through an ornamental shell and the flow-splitting base to enter a room. The main engine and the bottom base can also be assembled to work independently.