Tool and method for quickly installing fastener in narrow space

The invention discloses a tool and method for rapidly installing a fastener in a narrow space, and relates to the field of part assembly. The installation tool comprises a screwdriver handle, a screwdriver rod, a sleeve and a spring; the screwdriver handle is connected to one end of the screwdriver rod, a first limiting part and a second limiting part are arranged on the screwdriver rod, the screwdriver rod is sleeved with the spring and located between the first limiting part and the second limiting part, the spring and the second limiting part are sleeved with the sleeve, the first limiting part is located between the sleeve and the screwdriver handle, and the second limiting part is located between the sleeve and the screwdriver handle. The spring moves together with the sleeve towards the end part of the screwdriver handle; a conical step is arranged on the inner side of the end, away from the screwdriver handle, of the sleeve, the minimum inner diameter of the conical step is smaller than the maximum dia