The invention discloses an inclination detection device for a transmission line tower and a detection method for the inclination detection device. The inclination detection device comprises a single-chip microcomputer, a power source, an acceleration inclination angle sensor, a WiFi wireless module and a receiving system; WiFi is adopted to transmit data of a transmission line tower inclination signal; a tower inclination angle is displayed by mobile phone client software in real time; when an inclination angle is greater than a set value, an alarm signal is sent so as to realize detection of tower inclination. The inclination detection device provided by the invention is simple, feasible and convenient to use.