The invention discloses a new added formwork construction method and a guardrail structure. According to the method, before a prefabricated beam is lifted, the lower portions of new added formwork guardrails are fixed to boundary beams on the two sides of the prefabricated beam, after the prefabricated beam is lifted, square tubes are inserted into the upper portions of the new added formwork guardrails and fixed through plug pings, and accordingly formwork and guardrail integration is achieved. After the new added formwork guardrails are installed, both construction of outer formworks and outer operation protection are completed, protection and formwork integration are achieved, operation is easy and convenient, the cost is reduced, and the construction method is suitable for popularization of assembly type project protection; and according to the new added formwork construction method and the guardrail structure, the structure is simple, prefabrication is convenient, and the practicability is high.