There are more stringent requirements of return difference and rigidity for precision reducer used in heavy industrial robot,the return difference and rigidity of heavy type 2K- V reducer can be tested by the self- developed experiment device,the comparative test research of similar products in abroad is also carried out,and the test torsion stiffness curves are drawn. By contrast experiment test results analysis,the return difference and rigidity of domestic heavy type 2K- V reducer comes up to the requirements of international standards,and a kind of effective means for evaluating the characteristic of heavy precision reducer is provided by the establishment test platform.