Plastic explosion-proof box and assembling method

The invention relates to the field of electrical equipment safety protection, in particular to a plastic explosion-proof box. The plastic explosion-proof box comprises a box body made of plastic, a box cover and a plurality of connecting assemblies connecting the box body and the box cover. The connecting assembly comprises a sliding base installed on the box body and a connecting shaft fixedly connected with the box cover. A mounting groove is formed in the top of the box body, and the sliding seat is vertically inserted into the mounting groove and is in sliding fit with the mounting groove; the sliding seat comprises a side wall and a bottom plate, and a via hole is formed in the bottom plate; a first bolt extending upwards is screwed and fixed to the bottom of the mounting groove, and the first bolt penetrates through a via hole of the bottom plate and extends into the sliding seat; the sliding seat can be inserted into the bottom of the mounting groove when moving downwards, and the sliding seat moves up