AbstractAn elastohydrodynamic model of ferrofluid‐lubricated involute spur gears was established, and transient thermal elastohydrodynamic lubrication (EHL) analysis was conducted using multigrid method and multigrid integral method. The transient lubricant film thickness, pressure, and friction coefficient characteristics of the spur gears were compared under different carrier fluid ferrofluids. Ester‐based H01 ferrofluid was selected to further examine the lubricant film elastohydrodynamic characteristics of the involute spur gears under different loads and speeds. The results indicated that the film thickness and the inlet area pressure were the largest when hydrocarbon‐based E02 ferrofluid was used for lubrication and were the smallest when ester‐based ferrofluid H01 was used for lubrication. When ester‐based H01 ferrofluid was used, the film thickness, the inlet area pressure, and the second pressure peak increased with the increase of speed, and the second pressure peak shifted toward the inlet area. The friction coefficient and the maximum temperature gradually decreased with the increase of speed, and the second pressure peak, the friction coefficient, and the maximum temperature gradually increased with the increase of load, while the film thickness gradually decreased.