Objective This study aims to investigate the impact of cultivation time on dendritic cells （DCs） and their derived exosomes' expression of immune?related membrane proteins （CD80， MHC?Ⅰ， MHC?Ⅱ） and provides experimental evidence for future research. Methods Mouse bone marrow cells were induced to differentiate into DCs using GM?CSF and IL?4， followed by maturation stimulation withTNF?α. Exosomes were extracted using ultracentrifugation.Western blot and Amnis image flow cytometry were used to identify exosomes derived from mouse DCs. Amnis image flow cytometry was used to detect the expression of immune?related proteins CD80， CD11c， MHC?Ⅰ， and MHC?Ⅱ in mouse DCs and their exosomes. Results After 5 days of in vitro cultivation， more than 50% of dendritic cells expressed CD80， CD11c， MHC?Ⅰ， and MHC?Ⅱ， reaching the highest level on day 13. The positivity rates were as follows： CD80 （97.29 ± 0.63） %， CD11c （92.31 ± 1.18） %， MHC?Ⅰ（97.91 ± 0.49） %， and MHC?Ⅱ（97.91 ± 0.49） %. The differences were statistically significant （P < 0.001）. The expression gradually decreased after day 13， but approximately 80% of DC cells still expressed MHC?Ⅰ and MHC?Ⅱ immune molecules on day 30. The expression levels of CD80， CD11c， and MHC?Ⅱ on the exosome membrane were highest on day 5 and then decreased overall with prolonged cultivation time， except for MHC?Ⅰ molecules. The differences were statistically significant （P < 0.01）. Conclusions In vitro?cultured mouse dendritic cells express high levels of immune?related membrane proteins and can be stably maintained for a long time under suitable culture conditions. The secreted exosomes also carry abundant immune?related membrane proteins， but no significant correlation was found between the immune?related proteins on the dendritic cell surface and the exosome membrane surface.