Surface molecule and atom adsorption behaviors in LAO/STO heterointerface have been investigated with density functional theory (DFT) calculations.The results indicate surface polar molecule adsorption can regulate the carrier mobility in LAO/STO via the control of charge transfer between the surface states of LAO and the conductivity buried in the STO.The oxygen vacancies on the LAO surfaces take primary effect in surface adsorption process.Furthermore,many atoms (H,Cu and Si) adsorption on LAO surfaces can donate electrons to the LAO/STO interfaces and effectively enhance the carrier concentration of 2DEG.