The invention provides a system and a method for anti-sway control of a crane. The system comprises a deviation angle monitoring unit and a frequency converter control unit, wherein the deviation angle monitoring unit is used for calculating a deviation angle a of a steel wire rope in real time; the frequency converter control unit is used for changing an output frequency of an amplitude-variable frequency converter into a first frequency when the deviation angle a reaches a preset value, and simultaneously increasing the output frequency of the amplitude-variable frequency converter to a second frequency by taking a cotangent value of the current deviation angle a as an acceleration and keeping the second frequency unchanged, in an acceleration process; and the frequency converter control unit is also used for changing the output frequency of the amplitude-variable frequency converter into the second frequency when the deviation angle a reaches a preset value, and simultaneously reducing the output frequency of the amplitude-variable frequency converter by taking the cotangent value of the current deviation angle a as a deceleration, in a descending process. According to the system and the method for the anti-sway control of the crane, which is provided by the invention, by controlling the output frequency of the amplitude-variable frequency converter to eliminate the sway occurring during a horizontal load movement, the system for the anti-sway control of the crane is not only simple in structure but also convenient to debug.