The invention relates to a method for separation of sugar acid from a corn straw acidolysis solution by a sequential simulant moving bed. The method specifically includes: separation of the corn straw acidolysis solution by sequential simulant moving bed chromatography separation equipment in three stages: a separation stage, which consists of connecting 8 chromatographic columns in series, pumping out the liquid from a third column by a circulating pump therebelow and injecting the liquid into a fourth column, injecting the liquid from the fourth column into a fifth column, and repeating the operation cyclically in order; a desorption stage, which consists of injecting a desorption agent from the upper part of a first column, and discharging a sulfuric acid solution at the bottom of a sixth column; and a feed desorption stage, which consists of injecting a desorption agent from the upper part of the first column, injecting the corn straw acidolysis solution from the upper part of the fifth chromatographic column, discharging a sugar solution from the bottom of the first column, and discharging a sulfuric acid solution from the bottom of the sixth chromatographic column, with the separated sulfuric acid solution having a concentration of 210mg/mL-320mg/mL and the sugar solution having a concentration of 20mg/mL-41mg/mL; concentration and recovery of the sulfuric acid solution; and filtering and concentration of the sugar solution. According to the method provided by the invention, the separated sulfuric acid and sugar solution have a high concentration, thus solving the problems of difficult sulfuric acid recovery and high cost in corn straw reutilization.