For the number of inversion is decided by the effective pumping power provided by xenon flashlamp, the xenon discharge circuit and flashlamp radiation numerical model are built. With the use of the numerical method and the model above, the xenon flashlamp characters under different circuit parameters are calculated and compared to the experimental results. Two more practical concepts effective radiation efficiency and effective spectral efficiency are defined, to select optimal pumping energy and power entering xenon lamp. The results show that simulated annealing algorithm can be used to choose best capacitor and inductance rapidly , when the coefficients of xenon lamp and operating voltage remain constant. And the optimal power entering the lamp is also picked in this way. This method not only avoids the lowering of valuable energy proportion in the pumping area due to the violet-shift in spectrum, but also guarantees the life of the xenon lamp.