The invention relates to a synchronous construction method of near height-unequal foundation pit. The construction method comprises the main steps of: adjusting the height of a ground continuous wall and the position of a steel support; constructing the ground continuous wall; constructing a SMW construction pile; constructing a SMW construction pile crown beam and a concrete support; excavating deep foundation pit and shallow foundation pit earth to the bottom of the steel support; erecting the steel support; excavating the deep foundation pit and shallow foundation pit earth; constructing a baseplate of a deep foundation pit structure; dismounting the steel support; constructing a side wall of the deep foundation pit structure; synchronously constructing a top plate of the deep foundation pit structure and a baseplate of a shallow foundation pit structure; constructing a side wall of the shallow foundation pit structure; filling the earth at the upper part of the top plate of the deep foundation pit; dismounting the concrete support; and the like. The construction method has the following beneficial effects: the top surface elevation of the ground continuous wall of the deep foundation pit is parallel to the bottom of the shallow foundation pit, so that the height of the ground continuous wall is reduced, and the engineering quantity of an envelop structure is reduced; and the earth excavation of the deep foundation pit and the shallow foundation pit and the construction of a main body structure are convenient, so that repeated procedure conversion is reduced, the cross operation is prevented, and the efficiency is improved.