The invention discloses a reversing system applicable to a complicated environment, a robot, an application and a method. The reversing system comprises a chassis, wherein driving wheels are arranged on one side of the chassis, and universal wheels are arranged on the other side of the chassis; the upper part of each universal wheel is connected with an electromagnetic clutch, and a positioning rotation device is arranged between a stator and a rotor of the electromagnetic clutch and drives the rotor to rotate to the set position automatically when the electromagnetic clutch is powered on. Each positioning rotation device of the reversing system is simple in structure, ingenious in conception and firm and reliable in performance, can adjust the traveling direction of the corresponding universal wheel when encountering an obstacle, and the system can smoothly pass through the obstacle. A control method of the reversing system is simple, when the electromagnetic clutches are powered on, the positioning rotation devices drive the rotors to rotate to the set positions automatically, structures such as a steering motor and the like are not needed, a series of problems about direction judgment after addition of the steering motor are solved, and the practicability is high.