The method for switching stream media servers (SMS) includes following steps: S102, when determining the fault occurs at current SMS, set-top box reports information of fault to fault monitor server; S104, after receiving information of fault, the fault monitor server assigns valid SMS for the set-top box, and sends associated information of valid SMS to the set-top box: S106, based on associated information of valid SMS, the set-top box builds connection with the valid SMS. In the invention, when abnormity occurs at SMS, the set-top box can switch to new SMS within short time so as not to cause stopping user's service.