The ultra-high-strength steel (UHSS) plays an important role in the mechanical industry because of their special performances. The machinability of 30CrMnSiNi2A steel was studied in dry milling with two different coated tools in the present work. This paper introduced that 30CrMnSiNi2A steel was a kind of difficult-to-machine materials. The results showed that the cutting force components of feed direction and cutting width direction, i.e. F x and F y , increased slightly with increasing the cutting speed and feed rate. The values of axial force component F z were much larger than F x and F y , and increased obviously with increasing the milling speed. The workpiece surface had the minimum roughness at the cutting speed of 150 m/min. The physical vapor deposition (PVD) coated ((Ti, Al)N-TiN) insert was more suitable for machining 30CrMnSiNi2A steel than the chemical vapor deposition (CVD) coated (Ti(C, N)-Al 2 O 3 ) insert. Moreover, the main failure modes of PVD-coated insert were micro-chipping and coating spalling. The wear modes of CVD-coated insert were ploughing, coating spalling, and cratering. The serious adhesive wear and the abrasion with some adhesion were the main wear mechanism of PVD- and CVD-coated inserts, respectively. The ultra-high-strength steel (UHSS) plays an important role in the mechanical industry because of their special performances. The machinability of 30CrMnSiNi2A steel was studied in dry milling with two different coated tools in the present work. This paper introduced that 30CrMnSiNi2A steel was a kind of difficult-to-machine materials. The results showed that the cutting force components of the feed direction and cutting width directions, ie F x and F y, increased slightly with increasing the cutting speed and feed rate. The values ​​of axial force component F z were much larger than F x and F y, and increased obviously with increasing milling speed. The workpiece surface had the minimum roughness at the cutting speed of 150 m / min. The physical vapor deposition (PVD) coated ((Ti , Al) N-TiN) insert was more suitable for machining 30CrMnSiNi2A steel than the chemical vapor deposition (CVD) coated (Ti (C, N) -Al 2 O 3) insert. were mic ro-chipping and coating spalling. The wear modes of CVD-coated insert were plowed, coating spalling, and cratering. The serious adhesive wear and the abrasion with some adhesion were the main wear mechanism of PVD- and CVD-coated inserts, respectively.