An ancillary system for surgery is provided. The ancillary system includes a trocar, a scalpel device and an exhaust device. The scalpel device includes a blade portion and a connecting arm. The exhaust device encapsulates at least a portion of the connecting arm of the scalpel device. The exhaust device is detachable from the scalpel device, and is configured to remove smoke, body fluids or biological tissues generated during a surgery to effectively improve the surgical process.
