Oxygen‐containing groups are critical for RGO substrate to promote ESC adhesion and proliferation. The RGO‐30 substrates were annealed at room temperature, 300 and 600 °C, and are expressed as RGO‐RT, RGO‐300, and RGO‐600, respectively. a) Raman spectra of RGO‐RT, RGO‐300, and RGO‐600 substrates. b) The oxygen‐containing group content of the RGO‐RT, RGO‐300, and RGO‐600 substrates was analyzed by FTIR. c) The hydrophilicity of RGO‐RT, RGO‐300, and RGO‐600 substrates was detected by surface contact angle measurements. * p < 0.05, *** p < 0.001. d) SEM images with different magnifications of a single cell of 46C cultured on RGO‐RT, RGO‐300, or RGO‐600 substrate for 4 h. Magnifications: 150 × (the left column), 5000 × (the middle column), and 10 000 × (the right column). Scale bars: 300 µm in the left column, 5 µm in the middle column, and 4 µm in the right column. e) The relative cell viability of 46C cultured on RGO‐RT, RGO‐300, and RGO‐600 substrates for 48 h was detected by CCK‐8 kit. * p < 0.05, *** p < 0.001. f) The protein expression levels of Nanog and SSEA1 were assessed by immunofluorescent staining. Scale bar: 50 µm.