Abstract The effects of temperature and strain rate on the deformation microstructure and hardness of Al–Zn eutectoid damping alloy was systematically investigated. The results show that the deformed alloy is mainly composed of eutectoid structure with η-Zn distributing on α-Al matrix. There are two forms of η-Zn particles in the eutectoid structure of the deformed alloy. The first type of η-Zn particles (η-ZnI) have relatively large sizes and display irregular morphology; another type of η-Zn particles (η-ZnII) have relatively small sizes and are characterized by dispersion distribution. There exist predominant η-ZnI particles at lower temperature and higher strain rate while dominant η-ZnII particles at higher temperature and lower strain rate. The hardness of the Al–Zn eutectoid damping alloy shows an overall rising trend with increase in temperature and decrease in strain rate. In particular, the highest hardness values (up to 113.07 HB) are obtained at 648 K/0.01 s−1.