A lens shielding mechanism for shielding an area exposed from a front housing due to leftward and rightward movements of a lens, the shielding mechanism comprises a group of shielding sheets having a certain width; the group of shielding sheets comprises a first shielding sheet and a second shielding sheet connected together; the first shielding sheet is arranged on the left and right sides of the lens and is fixedly connected to the lens; the second shielding sheet is arranged on the left and right sides of the first shielding sheet, and the second shielding sheet is connected to the front housing and is moveable leftwardly and rightwardly with respect to the front housing; when the lens moves leftwardly and rightwardly by less than a certain distance, the lens drives the first shielding sheet to move, and the second shielding sheet does not move, and the area exposed from the front housing due to the leftward and rightward movements of the lens is shielded by the first shielding sheet; when the lens moves leftwardly and rightwardly to the certain distance, the lens drives the second shielding sheet to expand alternately, and the area exposed from the front housing due to the leftward and rightward movements of the lens is shielded by both the first shielding sheet and the second shielding sheet; wherein the upper portion and the lower portion of the lens are provided respectively with two protruding columns passing through the first shielding sheet, to achieve fixed connection of the first shielding sheet and the lens; the upper portion and the lower portion of the second shielding sheet are provided respectively with two limiting holes matching with the protruding columns, and the protruding column clips in the limiting hole and is slidable leftwardly and rightwardly in the limiting hole; a clip hook is provided on the front housing, a slot matching with the clip hook is provided at a middle position between the upper portion and the lower portion of the second shielding sheet, and the second shielding sheet is connected to the front housing via matching of the slot and the clip hook; when the lens moves leftwardly and rightwardly to a distance smaller than the length of the limiting hole, the protruding column on the lens slides in the limiting hole, the second shielding sheet does not move, and the area exposed from the front housing due to the leftward and rightward movements of the lens is shielded by the first shielding sheet; and when the lens moves leftwardly and rightwardly and drives the protruding column to move to the extreme position of the limiting hole, the protruding column drives the second shielding sheet to continue moving leftwardly and rightwardly with respect to the clip hook on the front housing within a length range of the slot, and the area exposed from the front housing due to the leftward and rightward movements of the lens is shielded by alternately expanding the first shielding sheet and the second shielding sheet. the first shielding sheet is arranged on the left and right sides of the lens and is fixedly connected to the lens; the second shielding sheet is arranged on the left and right sides of the first shielding sheet, and the second shielding sheet is connected to the front housing and is moveable leftwardly and rightwardly with respect to the front housing; when the lens moves leftwardly and rightwardly by less than a certain distance, the lens drives the first shielding sheet to move, and the second shielding sheet does not move, and the area exposed from the front housing due to the leftward and rightward movements of the lens is shielded by the first shielding sheet; when the lens moves leftwardly and rightwardly to the certain distance, the lens drives the second shielding sheet to expand alternately, and the area exposed from the front housing due to the leftward and rightward movements of the lens is shielded by both the first shielding sheet and the second shielding sheet; wherein the upper portion and the lower portion of the lens are provided respectively with two protruding columns passing through the first shielding sheet, to achieve fixed connection of the first shielding sheet and the lens; the upper portion and the lower portion of the second shielding sheet are provided respectively with two limiting holes matching with the protruding columns, and the protruding column clips in the limiting hole and is slidable leftwardly and rightwardly in the limiting hole; a clip hook is provided on the front housing, a slot matching with the clip hook is provided at a middle position between the upper portion and the lower portion of the second shielding sheet, and the second shielding sheet is connected to the front housing via matching of the slot and the clip hook; when the lens moves leftwardly and rightwardly to a distance smaller than the length of the limiting hole, the protruding column on the lens slides in the limiting hole, the second shielding sheet does not move, and the area exposed from the front housing due to the leftward and rightward movements of the lens is shielded by the first shielding sheet; and when the lens moves leftwardly and rightwardly and drives the protruding column to move to the extreme position of the limiting hole, the protruding column drives the second shielding sheet to continue moving leftwardly and rightwardly with respect to the clip hook on the front housing within a length range of the slot, and the area exposed from the front housing due to the leftward and rightward movements of the lens is shielded by alternately expanding the first shielding sheet and the second shielding sheet.