The acid-resistant and thermostable α-amylases is one of the important industrial enzyme preparation, which can hydrolyze starch under high temperature and low pH. The influence of thermal stability, pH stability and metal ions on the acid-resistant and thermostable α-amylases was outlined. The main strain resources were summarized. The research progress in strain improvement and archaea, including compound mutation of mutation breeding and gene engineering site-directed mutagenesis, was discussed.