A method of driving regulation for bipolar transistors in electronic ballast is provided. The method may include: sensing voltage at midpoint of half bridge of the transistors; producing a reference time signal according to a sync signal from a timer; producing actual time interval in this cycle by comparing rising edge of the voltage at midpoint of the half bridge of the transistors with rising edge of a driving signal for the transistors in upper bridge arm in each switching cycle; comparing the actual time interval with the reference time signal to determine pulse width of the driving signal; regulating, in which the driving signal in this switching cycle is prolonged relative to the driving signal in previous switching cycle if the actual time interval is larger than the reference time signal, while the driving signal in this switching cycle is shortened relative to the driving signal in previous switching cycle if the actual time interval is smaller than the reference time signal.