The invention discloses a manual-automatic integrated quasi-synchronized connection method and device applicable to conventional and digital stations. According to the method and the device, acquisition of digital and conventional analog voltage signals and switching signals can be realized, and after processing and computing of acquired data, a voltage difference, a frequency difference and a phase angle difference are reflected to a synchronizing dial plate. In a manual mode, a switch-on instruction is output through the digital quantity and a relay when the voltage difference, the frequency difference and the phase angle difference are in predetermined ranges and a switch-on switching signal is detected; in an automatic mode, the switch-on instruction is output through the digital quantity and the relay according to set leading time when switch-on conditions are met. Single functions of the conventional dial plate and quasi-synchronized connection device are improved, the requirements of an operator for manual and automatic quasi-synchronization are kept, the method and the device can meet the functional requirements of conventional stations, digital stations and conventional and digital mixed stations, and workload of operation and maintenance workers is reduced.