The invention provides a time synchronization keeping method and a time synchronization keeping system applied to a TD-LTE. The method comprises the steps as follows: a base station acquires a time synchronization signal, the time cycle of the synchronization signal is counted by using a counter generated by a local clock, a reference timer acting in base band treatment is configured according toa ratio of the actual counted point number in the time cycle and the standard point number, and the reference timer is adjusted in real time to achieve time synchronization correction. According to the method and system provided by the invention, the increasing of cost caused by hardware revision can be avoided, the time synchronization hopping caused the common correction mode is avoided, and theperformance requirement of time synchronization keeping is also met. In addition, the scheme has no affect on the treatment of system base band, low in complexity and prone to implementation, and thenew technical means for overcoming the prejudice of the prior art is provided in the industry, and the important market value is provided.