The invention relates to a telescopic combined double-layer drill rack, which consists of a hinged supporting seat 1, an inner upright post 2, slide rails 3, a cross support 4, a ring beam 5, outer upright posts 6, a supporting beam 7, an upper oil cylinder seat 8 and an oil cylinder 9. Two single-edge drill racks have the same structure, and the single-edge drill rack forms a rectangular double-layer sleeve barrel type by sleeving the outer upright post with the inner upright post. The top of the outer upright post is assembled with the upper oil cylinder seat and connected with two oil cylinder output shafts in parallel through the upper oil cylinder seat. The body of the oil cylinder is provided with a middle support and connected with the cross support, wherein the cross support is fixed in the inner upright post on the half upper part; and the bottom of the inner upright post is provided with the hinged supporting seat. The outer upright posts of the two single-edge drill racks are respectively connected with the supporting beam and the ring beam through bolts so as to ensure that the outer upright posts, the supporting beam and the ring beam form a door type whole. The inner sides corresponding to the two outer upright posts are respectively connected with the slide rail so as to ensure that a power head which is arranged on a disc rack 10 can move up and down. A lug plate on the outer side at the bottom end of each outer upright post is connected with two oil cylinder output shafts. The body of the oil cylinder is provided with the middle support and connected with the cross support, and the cross support is fixed on the disc rack.