The invention discloses a gantry-type bottom supporting brick loading machine. The gantry-type bottom supporting brick loading machine is characterized in that a rotary rack component is hoisted on the lower end of a gantry rack; the rotary rack component comprises a guide rail ring, a chain ring and a hoisting rail ring; a sliding hoister is arranged between the guide rail ring and the chain ring; a clutch device is arranged between the chain ring and the guide rail ring; the lower end of the clutch device is connected with a hoisting fixture through a traction mechanism; the hoisting fixturecomprises outer clamping plates arranged on two sides of a two-way cylinder; the inner side of each outer clamping plate is hinged to a middle clamping plate; the upper ends of the two sides of the middle clamping plates are hinged to an X-shaped moving rack and a herringbone moving rack; the lower end of the two-way cylinder is provided with a vertical cylinder; a sleeve pipe is arranged on thelower end of the vertical cylinder; two ends of the sleeve pipe are connected with telescopic shafts in a sleeving manner; the ends of the telescopic shafts are hinged to inner clamping plates; a roller shutter support plate is arranged in the inner cavity of the outer clamping plates; two sides of the lower ends of the outer clamping plates are provided with a support beam; and support plates arearranged on two sides of the bottoms of the outer clamping plates. By adopting the gantry-type bottom supporting brick loading machine, semi-automatic brick loading work can be realized; conveying efficiency is greatly improved; and meanwhile, bottom supporting clamping is adopted, so that safety performance is greatly improved.