next rru in an embodiment as for the uplink synchronization time delay the method for improving the synchronous precision of data transmission comprises the following steps the data frame is received by the antenna receive port of the rru and transmitted to the radio frequency module frame parsing is performed to the wireless frame impulse signal and the carrier data signal of the data frame and the maximum delay compensation time is set delay compensation is performed to the wireless frame impulse signal according to the transmission and buffering time and the maximum delay compensation time and then buffered to the signal output port of the rru and transmitted to the signal input port of the bbu adc analog digital conversion processing and ddc digital down conversion processing are performed to the carrier data signal and delay compensation is given to the carrier data signal according to the radio frequency module transmission time the adc processing time the ddc processing time the maximum delay compensation time and the transmission and buffering time the carrier data is performed with adc processing ddc processing and then buffered to the signal output port of the rru and transmitted to the signal input port of the bbu wherein the wireless frame impulse signal and the carrier data are sent to the signal output port of the rru simultaneously as for the rru multi level cascading of uplink synchronization time delay after the wireless impulse signal and the carrier data signal are buffered to the signal output port of the rru the current data frame and the next uplink data frame are performed.