The triangular track walking mechanism and mountain half track tractor relate to the field of agricultural machinery. The triangular track walking mechanism includes a driving wheel, a bracket, a track, a supporting device, a guiding device, and a tensioning device. The driving wheel is set at one end of the bracket, and the supporting device, the guiding device, and the tensioning device are all set at the end of the bracket away from the driving wheel. The guiding device and the tensioning device are set on both sides of the bracket. The driving wheel, the supporting device, the guiding device, and the tensioning device all cooperate with the same side of the track. The triangular track walking mechanism and the mountain half track tractor provided by this utility model are selectively connected to the vehicle body through the triangular track walking mechanism, which improves the working efficiency of the mountain half track tractor