OBJECTIVE To primarily embolize intracranial aneurysms with new-developed mechanically detachable coils, which is called Detachable Coil System (DCS). METHODS Five intracranial aneurysms were embolized with DCS, in which 2 were giant aneurysms. DCS with J coils were initially used to make baskets in giant aneurysms, and then other kinds of coils were utilized to pact the aneurysmal cavity. Whereas, spiral coils were mostly used in smaller aneurysms. Coils of DCS were detached by rotating the delivering wire after the coils were satisfactorily positioned in aneurysms. RESULTS Two of the 5 cases were totally occluded with DCS. Two was sub-totally embolized. Pushing, withdrawal, and adjusting of DCS were safe and efficient. Detachment of DCS was fast. In one case of wide-necked giant aneurysm, coils could not stay inside the aneurysm, which was treated by occlusion of the parent artery. CONCLUSIONS DCS is a new addition to the interventional radiologist's armamentarium. Detachment is faster. J coils are suitable for giant aneurysms for its unique way of coiling. But more evaluation depends on accumulation of the clinical usage.