Sudden lumbar pain when bending may have the following causes: first, acute sprain of the waist, when bending the waist muscles appear abnormal force, there can be a sprain of the lumbar muscles, then the relevant examination and X-ray, CT examination, to exclude other diseases, for diagnosis. Second, disorders of small joints, when the small joints are disordered, can also appear when bending sudden lumbar pain, often in a forced position, waist afraid to move, then to conduct CT examinations to exclude other diseases, often need to reset the Chinese medicine to relieve pain. Third, lumbar spine slippage or lumbar spine instability, when the lumbar spine slippage, instability, can also be very obvious lumbar pain when bending, this time to carry out the lumbar spine X-ray, CT examination, nuclear magnetic examination, for diagnosis and treatment.