The invention discloses an adjustable support leg hook type lifting double-locking mounting mechanism for electromechanical equipment in a substation. The mounting mechanism comprises a base joint which is arranged on a stud of a base of the mechanism, and a telescopic joint, wherein a fixed arm is hung and connected at the upper part of the telescopic joint, a telescopic arm which is used for locking is arranged in the fixed arm, and a hook for lifting the equipment is arranged at the front end of the telescopic arm through a pulley block and a sling; a counterweight trolley is arranged at the lower part of the base joint of the stud, an anti-overturning rope is arranged between the counterweight trolley and the telescopic joint for preventing the mechanism from overturning, and the telescopic joint has a self-locking function in the base joint of the stud so as to ensure that the telescopic joint cannot fall down naturally; and a lifting mechanism of the telescopic joint has the functions of locking and braking, can stay at any height, changes the operation form of manually mounting the equipment in a power transmission region in the past and eliminates the potential safety problems in the mounting operation process, thereby not only improving economic benefits, but also promoting safety benefits.