Objective  To evaluate the immunological effect of recombinant H7N9 influenza virus hemagglutinin (HA) subunit vaccine in animal. Methods  The secreted HA fragment was expressed by baculovirus expression system. With or without Al(OH)₃ adjuvant, BALB/c mice were immunized with recombinant H7N9 HA (rH7HA) by intrapperitoneal injection followed by H7N9 strain attack. The immune protection effect was analyzed. Results  rH7HA supplemented with Al(OH)₃ adjuvant induced higher IgG titer in serum by intraperitoneal injection than rH7HA group alone. The highest dose (1.500 μg) of rH7HA with adjuvant group induced 2¹⁵ IgG titer, and non-adjuvant group induced 2¹³ IgG titer, but there was no statistically significant difference, suggesting that 1.5 μg rH7HA was able to provide protection against homologous virus infection even without adjuvant. Conclusion  The secreted HA protein expressed by baculovirus system can protect mice against lethal dose of homologous virus infection by intraperitoneal injection.