Recently, Nanotechnology was being widely accepted in many fields due to its unique properties in enhancing the characteristics of many different kinds of materials, including asphalt binder. On the other hand, the usage of polymer nanocomposites for the production of durable asphalt mixtures has steadily replaced the use of polymer-modified binders. This study investigates the influence of nanosilica particles (NS) on rheological properties and mixture performance of asphalt modified with 2% waste polypropylene polymer (WPP). IN laboratory work, NS/WPP composite modified asphalt samples have been produced by adding three different percentages of NS particles (0.5, 1, and 2%) by weight of binder and 2 % WPP to control asphalt (60-70) penetration grade using a mechanical mixer and a homogenizer shear mixer with shear rate 27000 rpm for 10 min at mixing temperature (165 ±5) °C. The physical tests and Marshall stability were used to evaluate the NS/WPP composite modified asphalt binder properties and mixtures performance characteristics. This study found that 2 % of NS particles decrease the temperature sensitivity of WPP modified asphalt by 13% due to improving the hardness of the NS/WPP composite modified binder. The results also showed that the Marshall stability values of NS/WPP composite modified asphalt mixtures improved by 34.2% and 9.71% at 2 % NS compared with the control and WPP modified asphalt mixtures respectively. This suggests that the composite NS/WPP composite has a noticeable effect on the performance of the flexible pavement, thus increase paving’s service life.