Top connecting structure of all-underground laying type cable branch box

The invention discloses a top connecting structure of a full underground laying type cable branch box, which comprises a box body with an accommodating space inside, a waterproof sealing element arranged along the edge of the top surface of the box body, and an electromagnetic wave shielding sealing element attached in a preset interval of the waterproof sealing element, the abutting part abuts against the waterproof sealing part and the electromagnetic wave shielding sealing part, the abutting part is parallel to the top surface of the box body and extends for a preset distance, so that a sealed space is formed by the waterproof sealing part, the electromagnetic wave shielding sealing part and the top surface of the box body, and the ventilation part penetrates through the sealed space to enable the interior of the box body to be communicated with the outside; the ventilation part is provided with a first part provided with a top opening, a ventilation component connected with the first part and a sealing as