X-ray diffraction and photoemission measurements have been carried out for Bi2Sr2CaCu2-xSnxO8+δ system. With Sn doping, lattice parameters a and c change somewhat, O1s and Cu2p core le vels shift differently in binding energy. From the experiment, we can deduce tha t the Sn ions are mostly in divalent state at small amount of doping, and in tet ravalent state at high doping level. Doping with Sn may have less influence on t he superconductivity than that with other elements. The results support the conc lusion that chemical environment plays a major role in the shifts of all core le vels in the high Tc superconducting samples.