A master-slave system, comprising at least one slave device and a master device adapted to synchronize in time and communicate with the at least one slave device for recording generation of a specified event, the at least one slave device, comprising: a slave timer element, adapted for counting a current moment; a slave control element; an instruction executing element; and a log sending element, adapted for sending a first event log related to the specified event to the master device; and the master device comprising: a master timer element, adapted for acquiring a reference moment counted by the master timer element or received from an external time source; and an instruction sending element, adapted for instructing the slave device to synchronize a moment counted by the slave timer element of the slave device and the reference moment acquired by the master timer element by sending a time synchronization instruction corresponding to the reference moment acquired by the master timer element to the slave control element of the slave device, wherein the instruction executing element of the slave device is adapted to synchronize the moment counted by the slave timer element according to the time synchronization instruction received by the slave control element; the master device being characterized in further comprising: a log receiving element, adapted for receiving the first event log from the log sending element of the slave device, wherein the first event log is an information formed by associating a generation moment of the specified event in accordance with the synchronized time of the slave timer element with an information for determining the specified event, wherein the slave device is adapted to perform time synchronization periodically with the master device according to the time synchronization instruction. a slave timer element, adapted for counting a current moment; a slave control element; an instruction executing element; and a log sending element, adapted for sending a first event log related to the specified event to the master device; and a master timer element, adapted for acquiring a reference moment counted by the master timer element or received from an external time source; and an instruction sending element, adapted for instructing the slave device to synchronize a moment counted by the slave timer element of the slave device and the reference moment acquired by the master timer element by sending a time synchronization instruction corresponding to the reference moment acquired by the master timer element to the slave control element of the slave device, wherein the instruction executing element of the slave device is adapted to synchronize the moment counted by the slave timer element according to the time synchronization instruction received by the slave control element; the master device being characterized in further comprising: a log receiving element, adapted for receiving the first event log from the log sending element of the slave device, wherein the first event log is an information formed by associating a generation moment of the specified event in accordance with the synchronized time of the slave timer element with an information for determining the specified event, wherein the slave device is adapted to perform time synchronization periodically with the master device according to the time synchronization instruction. a log receiving element, adapted for receiving the first event log from the log sending element of the slave device, wherein the first event log is an information formed by associating a generation moment of the specified event in accordance with the synchronized time of the slave timer element with an information for determining the specified event, wherein the slave device is adapted to perform time synchronization periodically with the master device according to the time synchronization instruction.