Closed cabinet beneficial to heat dissipation and heat dissipation method of cabinet

The invention discloses a closed cabinet beneficial to heat dissipation and a heat dissipation method of cabinet. A first inner side vertical plate and a second inner side vertical plate which are connected with a top cabinet wall and a bottom cabinet wall of the box body cabinet are arranged in the left side and the right side of the interior of the box body cabinet respectively, the first innerside vertical plate and the second inner side vertical plate are matched with each other to form a heat dissipation working cavity in the box body cabinet, a heating component is arranged in the heatdissipation working cavity, an air inlet channel is formed in the space between the left side face of the first inner side vertical plate and the left side wall of the box body cabinet, the air inletchannel is communicated with cold air flow outside the box body cabinet through an air inlet, and a plurality of air injection openings communicated with the air inlet channel and the heat dissipationworking cavity are vertical