A disk-based fluid sample separation device including at least one air vent forming a part of a flow channel pattern on a microfluidic disk is disclosed. The fluid sample separation device is provided with an air vent sealing cover having at least through hole and is placed on the top surface of the disk. The air vent sealing cover is rotated with respect to the disk either at a first position or a second position. At the first position, the hole of the air vent sealing cover is in correspondence to the air vent of the flow channel pattern to control the sample liquid delivery. At the second position, the air vent of the flow channel pattern is closed. The flow channel pattern includes at least one sample storage reservoir, at least one sample processing reservoir, and at least one communication channel which is in fluid communication between the sample storage reservoir and the sample processing reservoir. In alternative, the status of the hole of the air vent sealing cover is controlled by a control unit.