Abstract: In this paper, a new cooking technique of cotton stalk with microwave radiation under atmospheric pressure was explored. Based on the analysis of cooking pulp effected by the main factors including total alkali content, dosage ratio of mixed-alkali, radiation time and radiation power, the optimum process condition determined by orthogonal experiments was provided as follows: total alkali content was 18%, the mass ratio of NaOH to Na2SO3 was 4:7, the solid-liquid ratio was 1:8 of and microwave heating time was 45 min. The results showed that the yield of cotton stalk pulp could be stabilized at around 53.3% and the hardness was about 20 under optimum conditions. The pulp obtained by this method was similar with conventional chemical pulp. This research studied a new way for application of cotton stalk resources and provided references for new sources of raw materials and pulping methods in Chinese pulp and paper industry.