Due to the increasing expansion of products made of plastic materials, high percentage of plastic waste enters the waste and waste annually, and the recycling of these plastic wastes is usually accompanied by decrease in their mechanical properties. One of the simplest and the most affordable ways to overcome the decline in mechanical properties during use recycled polymer, is achieving optimal combination virgin polymer and recycled polymer via mixing together. In order to produce products with both high quality and optimal mechanical properties will be desirable. Accordingly is beneficial for both environment and economic point of view, reducing use of virgin polymer.  In this study, in order to investigate the effect of weight percentage of recycled polyamide 6.6 with virgin polyamide 6.6 on the mechanical properties by injection molding proses, mix recycled polyamide 6.6 and virgin polyamide 6.6 with different weight percentages is prepared and then is injected. The results of mechanical tests on injected samples showed that adding more than 50% by weight of recycled polyamide 6.6 to virgin polymeric materials increased melt flow index, glass transition temperature and crystal temperature. While, the mechanical properties of samples decreased with increasing weight percentage of recycled polyamide in the composition. These changes were less for some properties such as tensile and flexural strength and more for impact resistance. Tensile and flexural strength and impact resistance in samples with 50% by weight of recycled polyamide in the composition, respectively, decreased by about 6%, 9% and 34% compared to the new polyamide sample.