The invention discloses an assembled guardrail. The assembled guardrail is mounted on a steel beam, and the upper surface of the steel beam protrudes outwardly along two sides of the length directionof the upper surface to form two mounting strips. The assembled guardrail comprises a bottom plate and multiple pairs of fixing plates and is characterized in that the fixing plates are rotatably parallelly mounted at the bottom of the bottom plate, and the fixing plates are distributed along two sides of the length direction of the bottom plate; a certain distance exists between each fixing plateand the bottom plate to form a space for accommodating the mounting strip for clamping the steel beam so as to clamp the steel beam. The assembled guardrail is convenient to assemble and use, good instabilizing effect, convenient to demount and good in reusing effect.