Step joint type self-staggered joint external corner template

The invention discloses a step joint type self-staggered joint external corner template, belongs to a building template, and aims to overcome the defects of slag inclusion and necking caused by high probability of mud leakage at a joint of an existing press board. A right-angle complete plate including two right-angle edges is integrally formed by plastic; a joint of a step is arranged on the inner sides of the two right-angle edges respectively; the joint of the step indicates a step form which is formed by a staggered joint lapping edge arranged within the thickness range of the right-angle edges and a square pillar-shaped staggered joint step formed on an included angle part of the right-angle complete plate; the thickness of the staggered joint lapping edge and the height of the step of the staggered joint step are 1/2 the plate thickness of the right-angle edges respectively; the thickness of the two right-angle edges is equal to the plate thickness of the template. During use, the template is placed at an external corner of to-be-cast concrete like an embedded cover plate and is lapped and coupled with the template on the plane of the to-be-cast concrete through the joint structure, the formwork supporting efficiency is high, mud leakage does not occur at the corner of the cast concrete, and the defects of slag inclusion and necking are avoided; the template is made of plastic and can be recycled after being damaged so as to reduce material waste.