The　hot　deformation　behavior　of　Al-Zn-Mg-Er-Zr　alloy　was　investigated　through　an　isothermal　compression　experiment　at　a　strain　rate　ranging　from　0.01　to　10　s(-1)　and　temperature　ranging　from　350　to　500　degrees　C.　The　constitutive　equation　of　thermal　deformation　characteristics　based　on　strain　was　established,　and　the　microstructure　(including　grain,　substructure　and　dynamic　precipitation)　under　different　deformation　conditions　was　analyzed.　It　is　shown　that　the　steady-state　flow　stress　can　be　described　using　the　hyperbolic　sinusoidal　constitutive　equation　with　a　deformation　activation　energy　of　160.03　kJ/mol.　Two　kinds　of　second　phases　exist　in　the　deformed　alloy;　one　is　the　eta　phase,　whose　size　and　quantity　changes　according　to　the　deformation　parameters,　and　the　other　is　spherical　Al-3(Er,　Zr)　particles　with　good　thermal　stability.　Both　kinds　of　particles　pin　the　dislocation.　However,　with　a　decrease　in　strain　rate　or　increase　in　temperature,　eta　phases　coarsen　and　their　density　decreases,　and　their　dislocation　locking　ability　is　weakened.　However,　the　size　of　Al-3(Er,　Zr)　particles　does　not　change　with　the　variation　in　deformation　conditions.　So,　at　higher　deformation　temperatures,　Al-3(Er,　Zr)　particles　still　pin　dislocations　and　thus　refine　the　subgrain　and　enhance　the　strength.　Compared　with　the　eta　phase,　Al-3(Er,　Zr)　particles　are　superior　for　dislocation　locking　during　hot　deformation.　A　strain　rate　ranging　from　0.1　to　1　s(-1)　and　a　deformation　temperature　ranging　from　450　to　500　degrees　C　form　the　safest　hot　working　domain　in　the　processing　map.