Children with leg pain usually appear to have pain around the knee joint or on the front side of the calf, and children with leg pain can find out the cause of leg pain after examination. 1, the leg pain caused by rheumatic and rheumatoid arthritis: need to do rheumatic and rheumatoid related examination, blood sedimentation examination, if there are problems, need to give the corresponding anti-rheumatic and rheumatoid drugs for treatment, treatment time is relatively long, but early treatment can prevent complications and the occurrence of bone deformities. 2.Pain caused by trauma: if the baby has obvious, afraid to walk, abnormal joint movement symptoms, consider fracture, need to take a film, fracture needs surgery. 3.Baby with pain mainly at night, paroxysmal pain: consider calcium deficiency or growing pains, need to check the trace elements, blood vitamin D concentration check, if there is no vitamin D and calcium deficiency, consider growing pains. Growing pains are a kind of muscular pain, caused by muscle spasm during the growth process, and need to be given hot compresses every night to relieve the symptoms. 4, leukemia invasion of bones and bone tumors: can also cause persistent leg pain, also need to check except.