The invention discloses an orthopedic splint mounting and fastening device convenient to adjust for the orthopedics department, and relates to the technical field of orthopedic appliances. The device comprises an upper fastening assembly, a lower fastening assembly, a first electric push rod, a breathable arc-shaped clamping plate and a sealed arc-shaped clamping plate, the upper fastening assembly comprises a left upper fastening block and a right upper fastening block, and the lower fastening assembly comprises a left lower fastening block and a right lower fastening block. According to the orthopedic splint mounting and fastening device, the arranged breathable arc-shaped clamping plate is poor in breathable effect, the area between the upper fastening assembly and the lower fastening assembly can be easily exposed, medicine can be conveniently smeared on the leg, the injured area of the leg is nursed or the injured area of the leg is carefully scratched, so that thediscomfort of the leg injured area is relieved, and itching is relieved. The device is provided with an opening and closing assembly, the size of an inner ring of the device can be automatically adjusted according to the thickness of the leg, the breathable arc-shaped clamping plate and the sealed arc-shaped clamping plate are arranged, the device has two use modes, the use modes are diversified, and functionality is high.