In this research project, the detailed and regional demand for natural gas in Khuzestan province, according to each city, was simulated and estimated using energy system programming language, Leap. All sectors of the natural gas industry including domestic, commercial, industry, agriculture, transportation, petrochemicals, pumping stations and energy transmission stations, injection into oil reservoirs and oil and gas extraction, oil and gas refineries and electricity generation were accurately modelled and analyzed. Results including the annual demand process for natural gas, hour peak of gas demand and the number of potential customers in the 20-year horizons were calculated and extracted in the consumable parts of each city (cities in separated from and villages in a cumulative manner). The results of the project indicate that the total annual demand for natural gas in Khuzestan province will reach 56.6 billion cubic meters per year with considering the injection and 46.4 billion cubic meters without taking into account the injection in the perspective of 2025, due to the establishment of diverse, large and energy-intensive industries in the province. The daily peak of natural gas demand, with an injection of 226 million cubic meters per day, will amount to 198 million cubic meters per day, without injection. The province's gas demand forecast software was also prepared and presented with results. This software is flexible, which by training it to the respected experts, the company was able to make unpredictable changes and update it in the coming years. Examining the validity of the results of the project indicates its convergence with the total demand for natural gas in the country, and also in coordination with the opinions of the respected experts of the province gas.