ObjectiveTo explore the regulatory effects and mechanisms of Astragali Radix polysaccharide （APS） on inhibitor of differentiation1 （ID1） and protein kinase B （Akt） in gastric cancer. MethodsImmunohistochemical staining was used to detect the expression of ID1 and Akt in 61 gastric cancer tissue samples and 20 adjacent normal gastric tissue samples. Immunofluorescence was used to detect the localization of ID1 and Akt. The effects of APS at the concentrations of 0.625， 1.25， 2.5， 5， 10， 20 mg·L^-1 on the proliferation of gastric cancer MGC-803 cells were examined by the cell counting kit-8（CCK-8） method and the colony formation assay. The target information of APS was retrieved from the Traditional Chinese Medicine Systems Pharmacology and Analysis Platform and Swiss Target Prediction. Keywords such as gastric cancer， gastric tumor， and stomach cancer were searched against GeneCards， UniProt， DisGeNET， and Online Mendelian Inheritance in Man （OMIM） for the screening of gastric cancer-related targets. The online tool jvenn was used to create the Venn diagram to identify the common targets， and STRING and Cytoscape were used to construct the protein-protein interaction network. Gene Ontology （GO） and Kyoto Encyclopedia of Genes and Genomes （KEGG） pathway enrichment analyses were conducted via R 4.2.2 to predict the potential roles of APS in the development of gastric cancer. The cell scratch assay was employed to assess the effect of APS on the migration of MGC-803 cells. The protein and mRNA levels of ID1 and Akt in the cells treated with APS were determined by Western blot and Real-time PCR， respectively. ResultsCompared with the adjacent normal gastric tissue， the gastric adenocarcinoma tissue showed increased positive expression of ID1 （χ² =81.00， P<0.01）. Immunofluorescence detection showed that ID1 and Akt were mainly located in the cytoplasm of gastric adenocarcinoma cells. Bioinformatics analysis identified 14 common genes shared between APS and gastric cancer. The average degree of protein-protein interaction network nodes was 14.29. GO and KEGG pathway enrichment results showed that ID1 and Akt were significantly enriched in the Rap1 and phosphatidylinositol-3-kinase （PI3K） /Akt signaling pathways. Cell experiments demonstrated that 5-fluorouracil （0.1 mg·L^-1） and APS （10， 20 mg·L^-1） groups showed decreased cell proliferation， migration， and colony formation. Compared with the control group， 10， 20 mg·L^-1 APS inhibited the proliferation of MGC-803 cells （P<0.01）， with 10 mg·L^-1 APS demonstrating stronger inhibitory effect. In addition， APS at 10， 20 mg·L^-1 inhibited the migration （P<0.01） and colony formation （P<0.05， P<0.01） of MGC-803 cells. Compared with the control group， APS at 10， 20 mg·L^-1 down-regulated the protein levels of ID1 （P<0.01） and Akt （P<0.05） and the mRNA levels of ID1 （P<0.05， P<0.01） and Akt （P<0.05， P<0.01） in MGC-803 cells. ConclusionID1 and Akt are highly expressed in the gastric adenocarcinoma tissue， which may be related to the development of gastric cancer. APS can down-regulate the protein and mRNA levels of ID1 and Akt to exert anti-tumor effects， which is expected to provide new therapeutic targets for gastric cancer treatment.