A mixed solution of 100 mmol/L NaHCO? and Na?CO? with molar ratio of 1∶1 and sodium nitroprusside （SNP） as the exogenous NO donor was used to simulate saline-alkali stress to study the molecular mechanism of exogenous nitric oxide （NO） regulating lupine’s response to saline-alkaline stress. 7 treatments including blank control， saline-alkaline stress control （100 mmol/L saline-alkaline mixed solution）， and SNP treatments with 5 concentration gradients （50， 100， 150， 200 and 250 μmol/L） under saline alkali stress were set up. The content of soluble sugar， the activity of sucrose phosphate synthase and sucrose synthase in the plants were measured. The transcriptome of the materials in the group with optimal concentration SNP treatment and the control group under saline-alkaline stress was sequenced. Results showed that exogenous NO increased the content of soluble sugar and enhanced the activity of sucrose synthase and sucrose phosphate synthase involved in synthesizing sucrose in seedlings of lupine under saline alkali stress. Exogenous NO treatment regulated the expression of genes encoding key enzyme in the pathway of sugar metabolism in seedlings of lupine， with upregulation of β-fructofuranosidase， sucrose synthase， and β-glucosidase， and downregulation of GDP mannose 4，6-dehydratase and 1，6-diphosphate fructose aldolase （class Ⅰ）. The differential transcription factors regulated by exogenous NO in response to saline-alkaline stress in lupine mainly included bHLH， ERF， MYB_related，bZIP and C2H2. It is indicated that exogenous NO can enhance the saline-alkaline tolerance of lupine by regulating the expression of key genes and transcription factors in the pathway of sugar metabolism in lupine.