PYTHIA is a well established Monte Carlo event generator developed over the
past several decades with the experimental discoveries. The core of PYTHIA model
for soft hadronic interactions is based on a phenomenological adaptation, such as Multiple Parton Interaction (MPI) model,
to describe the non perturbative pp processes. A parameter study of this MPI model using best fit to the data published by ATLAS Collaboration is presented.
Altogether thirteen parameters have been investigated to find the most sensitive parameters to the selected data.
This type of study helps in better understanding and selection of sensitive parameters needed to be considered in PYTHIA6 tunes.