Abstarct: Today, oil and gas are considered as the main energy resources in the world but these resources are not spread steadily in the world. The necessity of using these recourses throughout the world requires that research in the scope of energy transfer from reservoirs to those regions that need higher consumption occur with a higher speed. Rapid increase in the demand for fuel and energy in regions that are encountering the lack of energy resources and surplus fuel transfer from regions that have these resources as the sources of resolving economic needs to regions with lack of resources has caused natural liquid gas as the most important way of energy resources transfer to be considered as the critical issue. Natural gas transfer done in different methods that regardless of transfer type, it is a process with high energy consumption. Natural gas liquefaction is usually used for far distances and large volumes. In this thesis, the goal is improving process performance and Efficiency second law of thermodynamics by changing effective process parameters and using streams with cold exergy and after analyzing pinch. Simulation and sensitivity analysis are done with Aspen-Hysys and then simulated case have been performed for three objectives functions of specific energy (the amount of energy required for one-kilogram product), total deconstruction exergy and total consumed work. By changing process and by using streams that have cold exergy, improved process performance and consumed energy for natural gas liquefaction will decrease as well. In this research by thermal recovery and study of effective factors, performance of mixed refrigerants process along improves with pre-cooling propane. The lowest specific energy provided in others researches, is 973 kg/kj that in this research has reduced to 845.2 kg/kj that has had a 13% improvement; on one hand, the obtained exergy output in this research is %46.8 that has a % 2.6 increase in comparison with similar studies. The analysis of pinch process, shows that system doesn’t need external hot energy and the minimum demand for external cold energy is 59.4 Mw that in this research is obtained 61.1 Mw. In this analysis, the obtained pinch point is 25 C֯.