We have investigated the structural and electrical properties of Si-Zn-Sn-O (SZTO) thin films deposited by RF magnetron sputtering at various deposition temperatures from RT to $350^{circ}C$. All the SZTO thin fims are amorphous structure. The mobility of SZTO thin film has been changed depending on the deposition temperature. SZTO thin film transistor shows mobility of 8.715 $cm^2/Vs$ at room temperature. We performed the electrical stress test by applying gate and drain voltage. SZTO thin film transistor shows good stability deposited at room temperature while showing poor stability deposited at $350^{circ}C$. As a result, the electrical performance and stability have been changed depending on deposition temperature mainly because high deposition temperature loosened the amorphous structure generating more oxygen vacancies.