The invention discloses a cutting tool having a fly-off prevention structure. The cutting tool having a tool body, a blade and a tool holder, the blade is installed on the tool holder, the tool body is provided with a tool slot, the tool holder is installed in the tool slot through a tool holder fastener, the front end of the tool slot is provided with a tool slot top surface along the cutting rotation direction of the cutting tool, one side of the blade facing the tool slot top surface is provided with a compaction inclined surface, a wedge is wedged between the tool slot top surface and the compaction inclined surface, and the wedge is connected with the tool slot through a wedge fastener. The cutting tool has the advantages of simple and compact structure, convenient processing and making, low production cost, convenient blade installing and dismounting, and good fly-off prevention effect.