The pain in the middle of the left foot can be caused by the following reasons: first, plantar fasciitis, plantar fasciitis is often caused by cold and strain on the plantar fascia and can have pain in the plantar fascia, which should be checked and examined early to exclude other diseases for early diagnosis and early treatment. Secondly, fatigue fracture, when the metatarsal bone of the foot has fatigue fracture, there can be pain on the bottom of the foot, then early physical examination, early foot x-ray, CT to early diagnosis. Third, metatarsophalangeal headitis, metatarsophalangeal headitis is due to strain or long distance walking, resulting in chronic inflammation of the metatarsal head, it is necessary to early physical examination, foot x-ray examination for early diagnosis and early treatment.