At present time, excilamps excited by a barrier discharge are the simplest and perspective as the sources of UV and VUV radiation. Much research is devoted to such excilamps. Traditionally, sinusoidal oscillators are used as excitation sources. The present work devoted to study the impact of excitation pulse form and other conditions on efficiency of a barrier KrCl and XeCl excilamps. The main results of the work performed are the following. The most high specific radiation power values were obtained at the excitation at the excilamp by voltage pulses of different polarity at maximum pulsed repetition rate (p.r.r) of 100 kHz, and made depending on operating conditions of excilamp, up to 120 mW/cm3. From the oscilloscope traces of voltage pulses, current and radiation it is seen that radiation is being registered within the whole current pulse duration. The most high values of average radiation power and efficiency were achieved, correspondingly, 100 W and 13%. Influence of pulse repetition rate of excitation of different temporal mode on the type of formed discharge, as well as efficiency and output parameters of Xe-Cl2 barrier discharge excilamp were studied. It has been found that at pulsed repetition rate of about 1 kHz and higher there are brightly glowing microdischarges - filaments observed in the discharge plasma. With this, the efficiency of excilamp practically keeps unchanged in the frequency range <EQ 1 kHz and monotonously decays either at further increase of excitation p.r.r. or at excitation power increase for the fixed frequency of excitation pulses.