The invention provides a four-rope grab bucket slag material grabbing system which comprises a computer, a PLC, a lifting frequency converter, an incremental encoder A, an opening-closing frequency converter, an incremental encoder B, a cart and trolley positioning device, a twisted rope detecting device, an overload limiter, a cart walking motor, a trolley walking motor, a runway girder, a travelling crane trolley and a grab bucket, wherein the travelling crane trolley is in sliding fit with the runway girder; the computer, the lifting frequency converter, the opening-closing frequency converter, the cart and trolley positioning device, the twisted rope detecting device, the overload limiter, the cart walking motor and the trolley walking motor are connected with the PLC separately; and the PLC and the computer realize data exchange through the wired or wireless communication manner. Compared with the existing manual operation, the four-rope grab bucket slag material grabbing system can still carry out safe operation on the condition that heavy fog or water vapor affects the sight line to reduce potential safety hazard and prevents a worker from operation under sulfur-containing water vapor to reduce health hazard.