The isothermal forging process has the ability to produce complex industrial parts from alloys that do not have high formability, such as aluminum alloys. Eliminating the temperature difference between the part and the die in this method eliminates the problem of cooling the part due to heat transfer to the die. In this study, the hot isothermal forging of AA6061 aluminum alloy in different conditions of process including lubricant type, dimensions and size of primary ingot, temperature and rate of deformation, to produce a complex industrial part numerically and experimentally was investigated. Deform 3D software was used to simulate this process. Comparison of experimental and numerical results showed a good agreement of results. The best dimension of the primary ingot for the studied piece is cylindrical with an initial diameter of 35mm and an initial height of 32mm. Increasing the temperature, reducing the deformation rate and using the appropriate lubricant reduced the amount of required forging force. Reducing the deformation rate from 25-2.5mm/s reduced the required forging force to 1.8 times. Increasing the forging temperature from 380 to 530℃ reduced the amount of forging force about 3.5 times and reducing the hardness of the part about 20%. The results showed that due to the complexity of the forging part, different areas of the part were affected by different strain values, which changes the percentage of secondary phases such as Mg₂Si phase in these areas.