The invention discloses a circuit domain switched fallback method and a terminal device, which shortens the searching time of the frequency point in the process of the CSFB where no frequency point is appointed. The circuit domain switched fallback method comprises steps of searching the frequency point of a neighboring area of a third communication system relative to the first communication system when the terminal fails to fall back from a first communication system to a second communication system, and residing on the frequency point of the neighboring area by the terminal if the frequency of the neighboring area can be resided. As a result, the invention can give a priority to searching the frequency point of the neighboring area of the third communication system relative to the first communication system when the frequency point selection of the second communication system is failed and the network appointed target frequency point is absent.The invention can shorten the frequency point searching time during the CSFB process where the appointed frequency point is absent and does not have to search all the frequency points.