The invention provides a denim fabric printing and dyeing process. The technical problems in the conventional printing and dyeing process that the fabric dye-uptake is low, the fabric easily fades due to repeated washing, the printing and dyeing effect is poor, and the like are solved. The denim fabric printing and dyeing process comprises the following steps: a, size mixing and printing, namely mixing printing paste, matching coating printing paste and sulfur dyestuff printing paste, printing a gray fabric through a decorating machine, and drying at the temperature of 90-98 DEG C; b, ageing, ageing the printed gray fabric through an ageing box at the temperature of 102-108 DEG C for 18-30 minutes; c, soaking, namely soaking the aged gray fabric by using sodium bicarbonate, and adding activated carbon; d, washing, namely washing the soaked gray fabric with hot water, soaping, cleaning with clean water, and finally, cleaning with clean water and dewatering; and e, drying, namely drying the washed gray fabric through a drying oven, wherein the drying temperature is 80-90 DEG C, and the drying time is 14-20 minutes, thereby obtaining the finished denim fabric. The denim fabric printing and dyeing process disclosed by the invention has the advantage of excellent printing effect.