The invention provides an underwater internal pressure compensation miniature dynamic seal rotation device and underwater monitoring equipment. The underwater internal pressure compensation miniature dynamic seal rotation device comprises a sealed cabin, a sealed cabin cover, a sealing body, and output shaft; the sealing body is provided with a step hole; the step hole is located at the end part of the sealing cabin and is fixedly connected with a spring seat; the output shaft is inserted in the step hole through the spring seat; the output shaft is sleeved by two tooth-shaped sealing rings; an isolating ring is disposed between the two tooth-shaped sealing rings; a sealing gasket is disposed between the step surface of the step hole and the tooth-shaped sealing rings; a spring is disposed between the spring seat and the tooth-shaped sealing rings; a detection window is disposed on the sealing cabin cover; an optical lens is fixed sealedly on the detection window. The underwater internal pressure compensation miniature dynamic seal rotation device of the invention can meet underwater dynamic seal requirements of different equipments, and the size is reduced; the weight is decreased; and the sealing performance is improved.