  The parton rescattering effect on the charged particle production in
ultra-relativistic p+p collisions is studied by the parton and hadron cascade
model, PACIAE, based on PYTHIA. We have calculated charged particle
pseudorapidity density ($dN_{ch}/d\eta$) at mid-rapidity and the pseudorapidity
distribution in inelastic and non-single diffractive p+p collisions at $\sqrt
s$=200, 900, 5500, and 14000 GeV with the PYTHIA and PACIAE models. The
calculated results of $\sqrt s$=900 GeV are well compared with the ALICE data.
The calculated $dN_{ch}/d\eta$ as a function of center-of-mass energy well
meets with the experimental data as well. Comparing the PYTHIA results (without
parton rescattering) with the PACIAE results (with parton rescattering), it
turned out that the parton rescattering effect plays an important role and this
effect increases with increasing center-of-mass energy.
