The utility model discloses an organic working medium of cocurrent flow radial inflow electricity generation expander belongs to low temperature waste heat recovery electricity generation technical field. It includes air inlet housing, the last first exit casing side by side of installing of air inlet housing, the second exit casing, still including the main shaft that is fixed with the turbine, the both ends of turbine respectively with first exit casing, it is sealed to be equipped with first comb tooth between the second exit casing, second comb tooth is sealed, be used for carrying out axial seal to organic working medium, be equipped with sealed apron on the exit casing, an organic working medium is sealed for being directed at it is sealed through first comb tooth, be equipped with contact mechanical sealing device and main shaft cooperation on the second exit casing, an organic working medium is sealed for being directed at it is sealed through second comb tooth. The utility model discloses an axial assembly, subdivision about not going on casing and internals has been avoided in the radial assembly dividing the face working medium that the deformation arouses to reveal in because of, has better sealed effect, has realized the zero leakage of organic working medium.