The invention provides a low-external-resistance supersonic/hypersonic speed inlet. A two-dimensional bump is arranged at an inlet of the supersonic/hypersonic speed inlet, and partial air discharge seam/hole arrays are arranged at the inward concave positions of the windward side and the leeward side; and meanwhile, an air discharge cavity below the bump is divided into two sub-cavities, and electromagnets and a metal plate with a folded corner are adopted for achieving control over opening and closing of the two air discharge sub-cavities. By means of control over opening and closing of the two air discharge sub-cavities, the low-external-resistance supersonic/hypersonic speed inlet can adapt to shock wave intensity and incidence point position changes brought by inlet working mach number and attitude angle changes, the optimal control ability on boundary layer separation caused by shock wave/boundary layer disturbance of a lip cover is obtained, and the remarkable effects of widening the working range of the low-external-resistance supersonic/hypersonic speed inlet and increasing the total pressure recovery coefficient are achieved. Due to the high flowing control ability of the low-external-resistance supersonic/hypersonic speed inlet, the inlet is allowed to adopt the design of the horizontal lip cover, and therefore the external pneumatic resistance of an aircraft can be effectively reduced.