The Inertia Dynamometer is a LOAD device.It applies a load to an engine or high speed rotating component so that test the performance of the engine under a variety of circumstances,Design and modify engines for improved fuel economy and emissions etc.So,I analyzed Dynamometer assembly by Static Analysis, Fatigue Analysis, Modal Analysis and Rotodynamic Analysis. Also need to check total assembly for whirling effect. An Inertia dynamometer rotated at 1000rpm is studied. In Static Analysis static loading conditions are used to find out Maximum stresses induced. Fatigue Analysis considering the combined loading of Bending and Torsion on an inertia dynamometer,analysis is carried out by using FEA and the results are comparing with the analytical approach. For Modal Analysis,This system is analyzing with FEA and experimental approach for finding the natural frequencies at first three mode shapes. Then the above natural frequencies and operational frequency of dynamometer are comparing to avoid vibration and failure of dynamometer caused by resonance.Then total assembly checked for Whirling effect to find out dynamic stability.