A pediatric oral examination tongue pressing system for a medical instrument comprises a first supporting device, a lighting device, a second supporting device, a tongue pressing device, a holding device, a fixing device, a third supporting device and an adjusting device. The first supporting device comprises an opening rod, a first supporting block and a first fixing block, the lighting device comprises a glass cover, a lighting lamp, a first fixing plate, a first connecting rod, a first support and a second support, the second supporting device comprises a second supporting block, a first bending rod, a second connecting rod and a third bending rod, the tongue pressing device comprises a third support, a second fixing block, a first tongue pressing plate, a second tongue pressing plate, a first bending plate, a first spring and a first fixing ring, the holding device comprises a fourth support, a holding ring, a first fixing rod, a holding frame, a second fixing rod and a third fixing rod, and the fixing device comprises a first fixing frame, a first diagonal rod and a fourth fixing rod. The pediatric oral examination tongue pressing system can be used for effectively opening a pediatric oral cavity to facilitate observation of medical staff.