The present invention discloses a heavy type gas turbine compressor exhaust cylinder casting process, in order to fully feed the casting solidification process, a cylinder body is vertically poured, an annular open riser is placed on the upper part of the cylinder body, a plurality of annular blind risers are placed on a sector, a chiller and a patch are simultaneously assembled for feeding the casting; a wood-type skin sample is used for shaping to ensure a precision casting size; an alkaline phenolic resin sand is used as back sand, chrome ore sand is used as a surface sand, and the air permeability and deformability of the sand mold surface can be increased; an open-type water nozzle is used for pouring, the chance of casting distortion can be reduced, and the casting quality is improved. Compared with the prior art, the beneficial effects are that: the technical problems of the defects of being complex in structure, large in volume, uneven in partial casting wall thickness, difficult to feed, easy to deform, easy to loosen, crack and deform, and the like of a heavy type gas turbine compressor exhaust cylinder steel casting part can be effectively solved.