The present invention discloses a spinal surgical instrument and a method of guiding thereof. The spinal surgical instrument is operated with a precedent device. The precedent device includes at least one guiding unit. The spinal surgical instrument includes an operating element, an extending element, a handling element and a guide element. One end of the extending element connects to the operating element. The other end of the extending element connects to the handling element. The guide element is disposed on the extending element and includes at least one guide hole. The operating element is guided to the precedent device by the passing of the guide hole along the guiding unit.