The paper on the position of lanthanide factors in useful complicated oxides; writer with the aid of using Ji Wu a et.al Explain that Complex oxides are branches of steel oxides that display promising properties. Lanthanide-containing complicated oxides, belong to ABO3 perovskite crystal shape that suggests so promising catalytic behaviour and are broadly utilized in renewable power applications. The digital systems of La and Sr in associated oxides had been studied the use of density useful theory approach are used on this research. Lanthanide has a partially occupied d-orbital and an atomic price of +2 in place of its nominal valence number (+3), while Sr does not. The simulation outcomes had been additionally showed with the aid of using electron density maps derived ,The life of an to be had d-orbital electron on La, in addition to the associated partial covalency, become proposed because the purpose of the catalytic behaviour located in experiments.