Abstract: In order to investigate the effect of transformation of nitrogen on pH value in course of vinegar composting, two-stage water-filled windrow fermentation method compost experiment was carried out. The amounts of total nitrogen, ammonia nitrogen, nitrate nitrogen and the temperature, organic matter and pH value were measured orderly. Results showed that the amounts of total nitrogen, ammonia nitrogen, nitrate nitrogen increase in the relative content, and pH value mounted up from 4.3 to 7.94 and eventually returns to about 6.3, and the content of organic matter descended from 91.8% to 83.2%, and the germination index reached 102.3%. Results indicate that vinegar residue compost has been full maturity.