YBa2Cu3O7-δ (YBCO) ceramic thin films were deposited by pulsed laser deposition on single crystal LaAlO3 (100) substrates in O2 partial pressure (PO2) from 400 to 500 mTorr and substrate temperature 740-780 ℃.The YBCO films with two thicknesses of ~300 and ~600 nm were prepared.Analysis of the temperature dependence of the AC susceptibility near the transition temperature,employing Beans critical state model,indicates that at substrate temperature 780 ℃,with increasing oxygen pressure from 400 to 500 mTorr,intergranular critical current density has decreased.