The invention relates to a gear case for a pasture bundling machine and belongs to the technical field of agricultural machinery. The gear case for the pasture bundling machine comprises a case body, a case cover, an input gear shaft, a middle shaft and an output shaft. The input gear shaft is inserted in the case body through a first bearing and a second bearing. A middle shaft spline, a middle gear, a pair of adjusting and control gears and a gear sleeve are arranged on the middle shaft. The gear sleeve is used for adjusting different work states of the gear case. The output shaft is sleeved with an output gear shaft. The gear case for the pasture bundling machine has the advantages of being compact in structural arrangement, attractive in appearance, good in reliability, small in size, high in transmission efficiency, convenient to operate and the like.