The impact in the nano scale, especially for the softer nanoparticles, is very important. As a result, the effect of different loadings on the contact process of nanoparticles and nanoparticles impact before initiation of contact are studied in this paper. To investigate the nanoparticles impact before contact begins, three theories including Hertz, JKR and Jamari are investigated. Regarding the impact, cubic and elliptical geometries are selected for nanoparticles. In order to study the contact process more comprehensively, the contact of nanoparticles is studied using the governing equations of elasticity. To validate the results, the developed models and an experimental sample are compared with each other. The sample has a relatively soft polystyrene surface. In comparison between the experimental results for force-displacement graph shows that by considering the initial impact the results accuracy improves up to 2.23%. (C) 2018 Elsevier B.V. All rights reserved.