The local atomic and electronic structure of La 0.5 Sr 0.5 MnO 3 was investigated at different annealing temperatures (TA) by X-ray absorption spectroscopy (XAS) and photoemission spectroscopy (XPS). The extended X-ray absorption fine structure indicates that the MnO 6 octahedral distortion is reduced by increasing TA. The chemical shift for the sample with TA = 1350° C measured by XPS of Mn 2p core level demonstrates the increasing of Mn 3+ ions content. From the deconvolution of valence band photoemission spectra, the number of eg electron is also proved to increase with increasing TA. It is also demonstrated that there is a strongest hybridization between O 2p and surrounding atomic orbital states in sample with TA = 1350° C , which is consistent with valence band photoemission.