Uniaxial tensile tests were conducted to investigate the hot tensile deformation behavior of 6061 aluminum alloy under various temperatures and strain rates. Fields−Backofen equation was employed to establish the constitutive model of 6061 aluminum alloy, which was used to construct the finite element model for multi-bosses formed by plate forging process at elevated temperature. In the combination of numerical simulations and experimental tests including micro-hardness and electron back-scattered diffraction (EBSD) examination, the influence of two main process parameters, namely deformation temperature and counter-punch force, on the boss deformation and microscopic characteristics of multi-bosses formed at elevated temperature was discussed. The results show that the constitutive equation adopted is adequate to predict the deformation behavior in the plate forging process. While a higher temperature can improve the formability due to the reduction of plastic deformation resistance, a higher counter-punch load is favorable to increase the boss height and risk of fracture around the punch radius at the same time. In addition, it is favorable to promote recrystallization and fabricate the cylindrical component with a more homogeneous microstructure at a higher deformation temperature. From a comprehensive consideration, the 623 K is taken as the optimized deformation temperature for the selected 6061 aluminum alloy.