The invention discloses a milling cutter-type big-gradient robot foot capable of actively changing soft terrains, relates to a robot foot, and solves the problem that according to a big-gradient robotfoot, the condition that a robot can climb up a slope with a big gradient is difficult to guarantee. A leg connecting flange and an ankle joint are assembled together and form a revolute pair; the lower end of a joint support is fixedly connected with the upper end of a milling cutter-type sole through a spring damping device; the lower part of a bearing mounting flange is embedded in the lower part of the milling cutter-type sole through a large bearing which is mounted in a sleeving manner; a small bearing is arranged in the upper part of the bearing mounting flange; a safety clutch and a rotating spindle are sequentially arranged in the center of the milling cutter-type sole from top to bottom; the upper part of the rotating spindle is mounted on the bearing mounting flange through thesmall bearing; the lower end of the rotating spindle is fixedly connected with the milling cutter-type sole; the upper end of the rotating spindle and the lower end of the safety clutch are fixedly connected through the connecting flange; and an output shaft of a speed reducer is mounted in the center hole of the safety clutch in a cooperative manner. The milling cutter-type big-gradient robot foot disclosed by the invention is used for a quadruped robot.