The comparative study on the two methods for determining the decomposing and retention rate of the organic material in fluvo-agvic soil in Henan province was carried out.The result showed that it conformed to the actual condition of the field to determine the decomposing and retention rate of the organic material with the method of nylon bag-potassium dichromate,so it's suggested that the relative study being performed with the method to replace the method of sand filtration tube-potassium dichromate.The humification cofficient of the wheat straw determined with the nylon bag method was 12.25%.