This paper presents a study on ’hard’ and ’soft’ interactions in (-p)p (pp) collisions using a phenomenological model of HIJING, the jet-cone reconstruction method is employed to select the ’hard’ and ’soft’ event sub-samples from minimum bias events. It is found that the HIJING model can reproduce the energy scaling behaviour of mean transverse momentum (〈pT〉) distributions of charged hadrons versus multiplicity (Nch) in ’soft’ events. From the PYTHIA simulation comparing with the HIJING model, the enhancement of the kaon and proton yields from ’hard’interactions comparing with ’soft’ interactions is observed to be due to the mini-jets effect. These mechanisms responsible for the increase of charged hadron’s 〈pT〉 are different in ’soft’ and ’hard’ interactions.