A noval all home-made avalanche transistor driver for single pulse selector with one side triggered, pulse width variable, and the pockels cell grounded, are described. A Marx Bank and an avalanche transistor chain absorber are combined to build a tiny high voltage nanosecond pulsewidth producer without any high voltage power supply. The output electric nanosecond pulse is about 4kv to meet the v of KDP. The risetime is less than 3ns, the avalanche absorber shortens the pulsewidth obviously. The triggered signal is taken from the intracavity polarizer ensuring the signal triggers the avalanche transistor or Marx Bank just in time to pick the peak pulse from the pulse train. We found several kinds of home made avalanche transistor, such as 3DG84I, 3DA151D, 3DA152E, that can be used as good as 2N5551 to build the single pulse slicer. The life time is over one million shots, the output stability is better than 5%, the mistrigger rate is less than 0. 1%, the single pulse selected probability is about 99. 9%, and the selected single pulse energy is larger than 500uj. The tasted parameters of the avalanche transistor, figues, dynamic measurement circuits and the selected picosecond laser pulse are given.