A structure for connecting an instrument drive to a sterile adapter, wherein the instrument drive has a surface on which a plurality of drive fixed engaging members are provided, and the sterile adapter is connected to the instrument drive; wherein the sterile adapter includes an adapter body and an adapter connecting assembly provided at the adapter body and configured to fix the adapter body to the instrument drive, the adapter connecting assembly includes a plurality of moveable engaging members cooperating with the plurality of drive fixed engaging members, each respective moveable engaging member of the plurality of moveable engaging members is moveable between an engagement position where the respective moveable engaging member is engaged with a corresponding drive fixed engaging member of the plurality of drive fixed engaging members and a detachment position where the respective moveable engaging member is detached from the corresponding drive fixed engaging member, and each of the plurality of moveable engaging member has a movement path relative to the adapter body parallel to a matching surface of the instrument drive matching the sterile adapter; and characterized in that two sets of drive fixed engaging members are provided on the surface of the instrument drive and are separated in a first direction by a drive transmission portion, and drive fixed engaging members of each set of the two sets of drive fixed engaging members are spaced from each other in a second direction transverse to the first direction; and wherein the adapter connecting assembly includes two moveable components, wherein each moveable component of the two moveable components includes one set of moveable engaging members corresponding to one respective set of drive fixed engaging members, and each moveable component is moveable relative to the adapter body to move the one set of moveable engaging members together between the engagement position and the detachment position. wherein the sterile adapter includes an adapter body and an adapter connecting assembly provided at the adapter body and configured to fix the adapter body to the instrument drive, the adapter connecting assembly includes a plurality of moveable engaging members cooperating with the plurality of drive fixed engaging members, each respective moveable engaging member of the plurality of moveable engaging members is moveable between an engagement position where the respective moveable engaging member is engaged with a corresponding drive fixed engaging member of the plurality of drive fixed engaging members and a detachment position where the respective moveable engaging member is detached from the corresponding drive fixed engaging member, and each of the plurality of moveable engaging member has a movement path relative to the adapter body parallel to a matching surface of the instrument drive matching the sterile adapter; and characterized in that two sets of drive fixed engaging members are provided on the surface of the instrument drive and are separated in a first direction by a drive transmission portion, and drive fixed engaging members of each set of the two sets of drive fixed engaging members are spaced from each other in a second direction transverse to the first direction; and wherein the adapter connecting assembly includes two moveable components, wherein each moveable component of the two moveable components includes one set of moveable engaging members corresponding to one respective set of drive fixed engaging members, and each moveable component is moveable relative to the adapter body to move the one set of moveable engaging members together between the engagement position and the detachment position.