【Objective】Thanks to its peculiar shape, fresh chicken droppings or manure, after solid-liquid separation, can be processed easily to remove sands and other inorganic substances therein. The solid part of the manure contains a large volume of lignocellulose. After being air-dried naturally, the solid part was treated with the SPORL(Sulfite pretreatment to overcome recalcitrance of lignocelluloses) method to explore feasibility of recycling the part as fertilizer. 【Method】Ammonium sulfite was used as catalyst, of which single factor tests were carried out to assess effects of four main influencing factors, namely, dosage of ammonium sulfite, temperature, temperature holding time and liquid/solid ratio. The tests show that the solid part, 5:1~15:1 in solid/liquid ratio, pretreated with 10%~20% of ammonium sulfite (relative to dry weight of the solid, w/w) at 120～140℃ for 30~60 min was high in organic matter content. Based on results of the single factor tests, conditions for the pretreatment were redesigned and optimized with the response surface methodology and content of organic matter in the solid as response indicators. The Design-Expert software was used to analyze variance of the multiple regression equation.【Result】The following findings were obtained. 1) When the ammonium sulfite dosage varied between 0% and 15%, the content of organic matter increased with rising ammonium sulfite dosage, but when it above 15%, the content decreased significantly. 2) When pretreated at 130℃, the solid part was the highest in organic matter content, reaching up to 319.4 g kg^-1, but the content turned downward gradually when the temperature continued to rise. 3) With the temperature holding time and the liquid-solid ratio increasing, the content of organic matter in the solid part decreased gradually. To sum up the content of organic matter was high in the solid part, 5:1～15:1 in solid/liquid ratio, pretreated with ammonium sulfite 10%～20% in dosage at 130～150℃ for 30～60 min. And it is predicted that the content may reach as high as 359.1 g kg^-1 in the solid part of chicken manure, 5:1 in solid/liquid ratio, pretreated with ammonium sulfite 13.4% in dosage at 127℃, for 30 min. In validation tests the content was 365.8 g kg^-1 on average, 6.7 g kg^-1 less than the predicted, which indicates that the regression equation is reliable and accurate for use to analyze and predict organic matter contents in the solid part of chicken manure.【Conclusion】In a word, in chicken manure treated with ammonium sulfite as catalyst in a reactor under high temperature and high pressure, lignosulfonates is formed and then turned into humic acid which contains mixture of lignohumic acids, fulvic acids, and a smaller proportion of low-molecular organic compounds. This method can be used to improve chicken droppings into organic manure with high organic matter content, and increase the value of value-added utilization of waste. So this method may have a good prospect of application to the industry of turning chicken droppings into organic manure.