The electronic structure of CdTe(111) surfaces with adsorbed alkali metals has been explored by synchrotron radiation and LMTO method. The experimental results showed that the surface states were redistributed when K-adsorbed and Fermi-pinning phenomena appeared. Theoretical calculations of K adsorbed on CdTe(111) surfaces agree well with the experiment. A systematic study of alkali metals adsorbed on CdTe(111) surfaces showed that the electronic structure characteristics not only depend on the atomic number of the alkali metals, but are also related to the core electron configurations.