The invention discloses a lumbar supporting air cushion for medical treatment, and relates to the technical field of medical equipment. The lumbar supporting air cushion comprises a base plate; one surface of the base plate is fixedly connected with an air cushion; an air outlet pipe runs through one surface of the air cushion; the peripheral lateral surface of the air outlet pipe is fixedly connected a detection device; one end of the air outlet pipe is fixedly connected with a regulation valve; an air inlet pipe runs through one surface of the air cushion; one end of the joint of the air inlet pipe and the air cushion is connected with a check valve; one end of the air inlet pipe is fixedly connected with an air inflation box; the detection device comprises a plurality of flow sensors; the inner surfaces of the plurality of flow sensors are sleeved with the peripheral lateral surface of the air outlet pipe. According to the invention, by a combined flow detection structure of the device device, a controller can accurately detect out an air outlet speed of the air cushion so as to control an air pump to carry out timely supplementation, keep an air volume inside the air cushion ina dynamic balanced state and keep a fit degree and elasticity of the air cushion always in an optimal state; the lumbar supporting air cushion has the advantage of improving comfort of the air cushion.