The hot deformation behavior and processing maps of as-homogenized Mg-Gd-Y-Zn-Mn alloy were investigated by hot compression tests performed at 350-500°C and strain rates ranging from 0.001/ s to 1/ s . The constitutive equation was established using hyperbolic law, and the activation energy of the alloy was calculated to be about 260.94 kJ/mol. Based on the dynamic material model, processing maps of as-homogenized Mg-Gd-Y-Zn-Mn deformed at strain values of 0.6,1.2 were drawn to study the hot workability of the alloy. The processing map developed at a strain of 1.2 shows two safety domains: one occurring at 460–500°C and strain rates ranging from 0.001 /s to 1 /s; the other occurring at 350–500°C, and strain rate ranging from 0.001/s to 0.005/s. The corresponding microstructure evolutions, with particular emphasis on the deformation mechanism of long-period stacking ordered phase (LPSO) in this alloy, were also discussed.