The invention relates to a construction method of a small-clear-distance laminated tunnel. The construction method comprises the following steps that a to-be-constructed lower layer tunnel and a to-be-constructed upper layer tunnel are subjected to in-advance support; the area, close to the upper layer tunnel, in the lower layer tunnel is excavated to form a first area, and corresponding construction of primary lining is conducted; a pilot tunnel is excavated at the position, opposite to the first area, inside the upper layer tunnel, and subjected to primary lining; a reinforcing device for sandwiched rock between the upper layer tunnel and the lower layer tunnel is constructed in the pilot tunnel; the rest part of the lower layer tunnel is excavated to subjected to corresponding construction of primary lining, and the lower layer tunnel is subjected to secondary lining construction; and the rest part of the upper layer tunnel is excavated and subjected to subsequent construction. According to the construction method, the pilot tunnel is arranged on the upper layer tunnel to enable a vibration wave to be propagated in air so as to reduce the influence of blasting of the upper layertunnel on a lower layer tunnel support structure and the sandwiched rock, mechanical equipment can be directly arranged in the pilot tunnel for operation, work such as sandwiched rock drilling is conducted from top to bottom, the problem that the small-clear-distance laminated tunnel is difficult to construct is solved, and thus the construction process is safer.