Endoplasmic reticulum stress (ERS) regulates the function of immune cells in the tumor microenvironment and suppresses the antitumor immune response. In order to formulate the TME of ERS-GC, we cocultured the human CAFs with the supernatant of human gastric cancer cells stimulated by TM. Mass spectrometry sequencing revealed that ERS state regulated the overexpression of 58 proteins and downregulation of the expression of 56 proteins in CAFs, including m6A-modified proteins and SEMA3A, an immunosuppression-related protein.