The invention discloses a multi-pack conveying box belt guardrail adjusting mechanism. The multi-pack conveying box belt guardrail adjusting mechanism comprises supporting pipes, bevel gearboxes, screws, a guardrail hanging rod assembly, guiding nuts, bearing pedestals and driving shafts. The supporting pipes include the left supporting pipe and the right supporting pipe; the screws include the upper screw and the lower screw which are arranged between the left supporting pipe and the right supporting pipe in parallel through the bearing pedestals; the upper screw and the lower screw are each provided with the corresponding guiding nut; the left side of the upper screw and the right side of the lower screw are provided with the bevel gearboxes; the driving shaft transversely penetrates the middle of the bevel gearbox; the guardrail hanging rod assembly comprises a first guardrail hanging rod and a second guardrail hanging rod; the upper screw and the lower screw are sleeved with the first guardrail hanging rod which is fixedly connected with the guiding nut arranged on the upper screw; and the lower screw is sleeved with the second guardrail hanging rod which is fixedly connected with the guiding nut arranged on the lower screw. A guardrail can be automatically adjusted as a whole, operation is easy, the guardrail adjusting time spent during product replacement is shortened, and the production efficiency is improved.