The invention relates to a lower end cap dropping site detection assembly in a filter core automatic assembly line. The lower end cap dropping site detection assembly in a filter core automatic assembly line includes a lower end cap detection assembly frame, a lower end cap and a revolving table, wherein the lower end cap is arranged in a location hole of the revolving table at the preorder station; a detection cylinder is fixedly hoisted below the lower end cap detection assembly frame; a round cover is fixedly arranged below a piston rod of the detection cylinder; three push rods are fixedly on the round cover in the lower circumferential direction at equal interval, and are corresponding to the location hole in the revolving table; an upper position magnetic switch, an intermediate position magnetic switch and a lower position magnetic switch are successively arranged on the side surface of the detection cylinder from top to bottom; and by utilizing the method of arranging the three magnetic switches on the side surface of the detection cylinder, and by means of the transmitting characteristic corresponding to different dropping site positions of the lower end cap, the lower end cap dropping site detection assembly in a filter core automatic assembly line can easily determine whether the lower end cap is dropped at the right site. The lower end cap dropping site detection assembly in a filter core automatic assembly line has the advantages of being simple and compact in structure and being relatively lower in cost.