An apparatus for automatically preparing liquid-based cytology slides by means of filtrationcomprising: at least one substrate for holding a vial containing specimen at a first position, a filter at a second position and a slide at a third position wherein said substrate is located at a first station; at least one working station comprising a working platform connected to said first station; the at least one working station comprising at least one first pick and place module configured to pick said vial from said substrate at said working station, transfer said vial to a second station for untightening and removing a cap of said vial, and transfer said vial to a first disposable station; at least one second pick and place module configured to pick said filter from said substrate at said working station, immerse said filter into said vial, transfer said filter to adhere to said slide and transfer said filter to a second disposable station; and at least one third pick and place module configured to pick said slide from said substrate at said working station, adhere said slide to said filter, and transfer said slide to a slide holder; characterized in that said first station includes a vertical rotary conveyor system comprising: a body frame; at least one actuator which is fixed to said body frame to actuate said vertical rotary conveyor system; a plurality of movable platforms on which said substrate can be loaded wherein said movable platforms are affixed to said body frame at a predetermined interval between the movable platforms, each movable platform being configured to connect with said working platform to enable continuous movement of said substrate from the first station to the working station; at least one chain guide rail supported by said body frame and configured to guide at least one roller chain; said roller chain being configured to connect with at least one sprocket to enable rotation and circulation of said vertical rotary conveyor system driven by the power of said actuator to form an endless track for enabling continuous movement of said substrate in clockwise or anticlockwise direction; and at least one alignment means configured to align said substrate with said movable platform. at least one substrate for holding a vial containing specimen at a first position, a filter at a second position and a slide at a third position wherein said substrate is located at a first station; at least one working station comprising a working platform connected to said first station; the at least one working station comprising at least one first pick and place module configured to pick said vial from said substrate at said working station, transfer said vial to a second station for untightening and removing a cap of said vial, and transfer said vial to a first disposable station; at least one second pick and place module configured to pick said filter from said substrate at said working station, immerse said filter into said vial, transfer said filter to adhere to said slide and transfer said filter to a second disposable station; and at least one third pick and place module configured to pick said slide from said substrate at said working station, adhere said slide to said filter, and transfer said slide to a slide holder; characterized in that a body frame; at least one actuator which is fixed to said body frame to actuate said vertical rotary conveyor system; a plurality of movable platforms on which said substrate can be loaded wherein said movable platforms are affixed to said body frame at a predetermined interval between the movable platforms, each movable platform being configured to connect with said working platform to enable continuous movement of said substrate from the first station to the working station; at least one chain guide rail supported by said body frame and configured to guide at least one roller chain; said roller chain being configured to connect with at least one sprocket to enable rotation and circulation of said vertical rotary conveyor system driven by the power of said actuator to form an endless track for enabling continuous movement of said substrate in clockwise or anticlockwise direction; and at least one alignment means configured to align said substrate with said movable platform.