Abstract. 2D PIC code simulations have been performed for the optimization of gas jet target parameters to achieve a maximal energy and efficiency of charged particle acceleration in planned experiments at the 20 TW picosecond SOKOL-P laser. These calculations specify an opportunity to obtain energy up to E e ∼ 200 MeV and efficiency e ∼ 10% for accelerated electrons and E p ∼ 30 − 50 MeV and p ∼ 5% for accelerated protons in these experiments at laser intensity I ∼ 5 · 10 19 W/cm 2 . They show the necessity of providing a formation of hydrogen jets with diameter ∼ 1 mm, a gas molecule concentration ∼ 2 · 10 19 cm −3 and steep density gradients ∼ 200 m at the edge of the gas jet target for achieving these parameters of laser accelerated particle beams.