A transmission timing adjustment method and device are provided. The method includes: determining, by a base station, a transmission delay between user equipment (UE) and the base station; generating, a timing advance (TA) quantized value according to the transmission delay, where the TA quantized value includes a base value and an offset value, quantization precision of the base value is first quantization precision MTs, quantization precision of the offset value is second quantization precision NTs, M is a positive integer less than or equal to 16, N is a nonnegative integer less than M, and Ts is a minimum time unit in a LTE system and has a value of 1/30.72 μs; and sending, by the base station, the TA quantized value to the UE, where the TA quantized value is used for uplink transmission timing adjustment of the UE. The embodiments facilitate network planning and optimization.