The drive laser system of the free electron laser (FEL) radio frequency (RF) photoinjector is introducted. The characteristic of the mode-locked oscillator controlling high current laser diode bar drive is presented in detail. The output power is 10.5 W, the timing jitter of the timing stabilizer is 0.56 ps. 11.9 ps Gaussian pulses of 266 nm wavelength are generated at a repetition rate 54.167 MHz. These “micropulses” are contained within a “macropulse” envelope as long as 6 μs. Micropulse energy of 5 μJ is abtained.