Corn starch as raw material is acidified by concentrated sulphuric acid to refine grape sugar. This article has made more overall lab studies concerning on the best condition of refining

the rate of regaining and the quality of product . It also has analysed and tested the quality of product systematically. Based on the above experiments

it has been turned out that the productive cycle of product and quality index compared with the information [1] is possible to use this lab method. It is simple to operate with short productive cycle and rate of output and quality farely improved. For the above mentioned features

this method is especially suitable for the rural enterprises to produce.