The generator for bulb type tubular turbine is installed hermetically in a bulb type metal case on the upper of turbine, and the principal axis of generator is connected to runner of turbine horizontally. The water current flows through flow channel axially, and runner vane in axial symmetry, and then flows out from straight taper draft tube. Shafting supporting structure, guide bearing and thrust bearing are all arranged in bulb body. Because of straight water flow, high hydraulic efficiency, biggish unit flow and higher unit rotating speed of tubular turbine, and prominent advantages of big water head range, high efficiency of bulb type one comparing to the other types of tubular turbine, bulb type tubular turbine has widely used at home and abroad. Its applicable water head is below 25m.