Abstract: A new type sewage submersible electric pump used for biogas broken-straw liquid transportation and no-blocking was designed according to traditional submersible pump defects in the process of conveying in biogas liquid.Problems of easy to plug，high cost and low gas production efficiency in biogas liquid conveying process were solved.A cutting system was designed for broken straw liquid.Cutting device on the pump shell bottom was fixed cutting board.A ring cutting knife was on the bottom of fixed cutting board.Between the ring cutting knife，there were some rotating spiral blades.The blades would cut the imported liquid straw in horizontal and vertical direction.There were also some circular cutting grooves fixed on top of cutting board.While impeller rotated，liquid straw would be cut secondly.This cutting action made liquid flow more smoothly.An inner loop cooling device was designed for submersible motor.The cooling device made submerge easy in a long time while the traditional submersible pumps couldn′t be.