The invention relates to a multifunctional horizontal rotating opening type inspection well lid and an opening method, and belongs to the technical field of inspection well lid equipment. According to the technical scheme, the multifunctional horizontal rotating opening type inspection well lid comprises a well lid base (1), H-shaped pins (4), a well lid body (5), a screw pin and a T-shaped anti-theft lock, a T-shaped guide groove (2) is formed in the well lid base (1), the well lid body (5) is connected with the well lid base (1) through the screw pin, the screw pin penetrates through the T-shaped guide groove (2), a rubber gasket (14) is arranged between the contact faces of the well lid body (5) and the well lid base, two or more H-shaped pins (4) are arranged on the well lid body (5) in the circumferential direction, and the T-shaped anti-theft lock matched with the T-shaped guide groove in shape is arranged on the T-shaped guide groove. The multifunctional horizontal rotating opening type inspection well lid and the opening method have the advantages that in the horizontal rotating opening or closing process, stereoscopic space is saved, meanwhile, personal injury accidents are prevented from being caused by accidental closing under the opening state, lifting and noise caused when vehicles and pedestrians pass through can be effectively prevented, and meanwhile the aim of theft prevention is achieved.