Sulfomethylated alkali lignins（SAL）with different sulfonic group content were prepared from acid precipitated alkali lignin（AL）through high temperature sulfomethylation. The influence of reaction condition on the sulfonic group content of SAL was studied. The high temperature stability and fiber staining were tested. SAL with different sulfonic group content were obtained by adjusting the dosage of Na2SO3 under the optimal modified conditions that the w (AL) was 25.0%，reaction Sulfomethylated alkali lignins（SAL）with different sulfonic group content were prepared from acid precipitated alkali lignin（AL）through high temperature sulfomethylation. The influence of reaction condition on the sulfonic group content of SAL was studied. The high temperature stability and fiber staining were tested. SAL with different sulfonic group content were obtained by adjusting the dosage of Na2SO3 under the optimal modified conditions that the w (AL) was 25.0%，reaction temperature was 180℃，reaction time was 4h，pH of solution was 11.0，n(Na2SO3)∶n(CH2O) was 3.5∶1. SALs with the sulfonic group content of 1.2~1.4 mmol?g-1 possesses good comprehensive performance, especially outstanding high temperature stability. The lowest average article size of dye dispersant after 130℃ treatment is 14.347μm，which is far less than those of commercial dye dispersant UNA（86.125μm）and NNO（59.886μm），however，they introduce some staining to fibers.