A therapeutic fluid infusion system for delivering a therapeutic fluid to a human body, the system comprising: a first assembly (20) comprising: a cradle (300) having a bottom surface configured for adhesion to a cutaneous region of the human body, a cannula (330), and a self-sealable septum (315), wherein a distal portion of the cannula (330) is configured for subcutaneous placement within the human body and wherein the self- sealable septum (315) separates a proximal portion of the cannula (330) from an external environment； and a second assembly (10) configured for removable attachment to the first assembly (20), the second assembly (10) comprising: a pump (120), a reservoir (220) for containing a therapeutic fluid, and a connecting lumen (250) configured to penetrate the self- sealable septum (315) in order to bring the second assembly (10) in fluid communication with the first assembly (20)； wherein the first and second assemblies (10, 20) are connectable by a sliding movement of the second assembly (10) relative to the first assembly (10) in a direction parallel to the bottom surface of the cradle (300), and wherein the second assembly (10) comprises: a disposable part (200) comprising the reservoir (220) and the connecting lumen (250)； and a reusable part (100) comprising at least one of: electronic components； a driving and pumping mechanism； a positive displacement pump provided with rotary wheel (110)； and a driving mechanism (120).
