The invention provides a capping device which is provided with a capping head body, first sliding bodies which are positioned on the capping head body and can slide up and down, and a capping door. The capping door is hinged with the capping head body and the first sliding bodies. The capping device is also provided with cap suction heads which can slide up and down. Middle sliding bodies which can slide up and down are arranged between the cap suction heads and the first sliding bodies. The capping device is also provided with a second spring, a first spring and a cap inlet slideway. The invention also provides a capping system which is provided with a plurality of above capping devices with the number of columns the same as that of the filling bottles. The cap suction heads of the capping device are connected together by a connection structure and are connected with a mechanism driving the cap suction heads to go up and down. The invention can complete capping stably, reliably and accurately and improve the work quality of the linear bottle filling equipment.