A kind of pressure control mechanism of suction unit,Comprising an ontology and a piston body,The ontology has an accommodating space,The accommodating space system is connected to two casings,The what accommodating space is movably arranged in the piston body,Wherein at least one casing has an oblique communication port,The piston body has an oblique side surface,In one first position of piston body what, the oblique side surface is bonded and closes the oblique communication port,Or the oblique side surface separates the what oblique communication port and two casings is made to be conducted with the accommodating space in one second position of piston body what,Thereby make piston body that can neatly move in the accommodating space of what ontology and control conducting or closing,To promote pumping efficiency.一種抽吸裝置之壓力控制機構，包含一本體及一活塞體，該本體具有一容置空間，該容置空間係連通二個套管，該活塞體移動地設置於該容置空間，其中該至少一個套管具有一斜向連通口，該活塞體具有一斜向側表面，在該活塞體於一第一位置該斜向側表面貼合且封閉該斜向連通口，或者在該活塞體於一第二位置該斜向側表面分離於該斜向連通口而使該二個套管與該容置空間相導通，藉此使活塞體可於本體之容置空間中靈活地移動而控制導通或封閉，以提升抽吸效率。
