Collective features of accelerated ions in the plasma focus are investigated theoretically by using a computer simulation. It is shown that an effective heating of ions by the acceleration of ions occurs without collisions in the collapse phase. A hybrid plasma diode model is used for the particle accelerations after disruption of the focused plasma by them=0 mode instability. It is shown that ions are efficiently accelerated in the disrupted region toward the downstream direction with respect to the discharge current, and that the energy of the accelerated ions is spread rather widely over the scale of 100 keV, as was observed in experiments.