The invention relates to a straight-swinging type grounding switch and a grounding cutter assembly thereof. The straight-swinging type grounding switch comprises a bracket, a grounding cutter assemblyand a driving structure, wherein the driving structure is used for being in transmission connection with a corresponding operating mechanism to drive the grounding cutter assembly to operate. The grounding cutter assembly comprises a guide rod connected with the bracket in a hinged manner, and a grounding cutter rod reciprocating along the extension direction of the guide rod, wherein the guide rod is provided with an upwards swinging closing limit and a downwards swinging opening limit on the swinging stroke of the guide rod, and the grounding cutter rod is provided with an extension closinglimit and a retraction opening limit on the reciprocating stroke. Under the driving action of the driving structure, the guide rod is switched between the upwards swinging closing limit and the downwards swinging opening limit, and during the process, the switching of the grounding cutter rod between the extension closing limit and the retraction closing limit is realized, and therefore the own length of the grounding cutter rod is changed, the transverse space occupied by the straight-swinging type grounding switch is reduced, and the range of location for the arrangement of the straight-swinging type grounding switch is expanded.