The invention provides a tobacco leaf prewilting baking process for a bulk curing barn. The tobacco leaf prewilting baking process for the bulk curing barn provided by the invention comprises the concrete steps of clamping the collected fresh tobacco leaves with a weaving pole or a tobacco clamp, prewilting on a shady tobacco hanging frame, so that the tobacco leaves meet prewilting requirement, then transferring the tobacco leaves into the bulk curing barn, and warming for twice to meet the yellowing requirement, wherein 2-3cm of apex of the tobacco leaves from a bottom shed to a middle shed is in an almost dry state; then warming for twice and baking until the tobacco leaves are dried into large winding drums and leaf blades are absolutely dry; and then warming at the speed of 0.5 DEG C per hour until the temperature is increased to 68 DEG C, controlling wet bulb temperature to be 42-43 DEG C, and maintaining rotating speed of a fan to be 720 revolutions until stems of the tobacco leaves are completely dry. By adopting the tobacco leaf prewilting baking process provided by the invention, tobacco leaf stacking capacity of the bulk curing barn is greatly increased, baking energy consumption is reduced, and the problem that starch content of the tobacco leaves after being baked and mixed colour tobacco proportion are high is solved, so that economic character of the tobacco leaves after being baked is improved.