In this thesis, the hot ring rolling of some titanium alloy parts was investigated using theoretical analysis based on FE methods. The main purpose of this project is to achieve the manufacturing technology of front and rear spool of jet motors using the ring rolling process. The main part of this thesis includes non-linear finite element analysis of ring rolling via ABAQUS simulation software. This analysis was executed for elastic-plastic rings using 3D mechanical-thermal coupled models. The presented analysis is unique in many viewpoints such as, complexity in shape of samples, the special geometry of the working rolls, complex movement of guide rolls, and the time consuming simulation. This thesis has been led to the development of two new approaches in the physical simulation of guide rolls and the simulation of complex parts using limited hardwares. The absence of guide rolls in the FE simulation of the ring rolling process leads to the deflection of the ring during the process and eventually suspending the simulation. Results prove the necessity of using guide rolls for stabilizing the operation. The first approach is capable of physically simulating the guide roll similar to the machine structure of the ring rolling system and calculating the approximate movement path of the guide roll. The forces and moments of the guide rolls are then calculated based on the approximated path. This approach requires further development for optimizing the movement path of the guide roll concluding in the optimization of the forces and moments of the guide roll. The maximum error of this approach is about 6% in calculating the roll force and 13% in calculating the side spread with reduction. The results show that including the guide roll in the simulation drastically improves the accuracy of the outputs. this approach can simulate the guide rolls for most complicated rings and has low computational time compared to other available methods. The second approach also simulates the ring rolling process uses separating of the ring in appropriate sections, separately FE simulating of each section and then gathering results. This approach is suitable for large number of the calculations and the inability of the available hardware for accomplishing the integrated simulation because of the low memory. The results show maximum of 13.5% error for this approach. The simulation results of these two parts, including the forces and moments of the work rolls, provide a guide for designing a ring rolling machine for manufacturing these two parts using appropriate reliability factor. The calculated parameters also provide a guide for rolling the parts by this machine. Key Words Hot Ring Rolling, FE Analysis, Guide Roll, Section Separation Method, Complex Profile.