The invention discloses a guide device with cooling and dedusting functions. The guide device with the cooling and dedusting functions comprises a guide cavity body, a detachable water pipe, a water pipeline, and a detachable dedusting nozzle. The upper part of the back end of the guide cavity body extends out to form a stretching installing part. The detachable water pipe is installed on the stretching installing part. The water receiving end of the water pipeline communicates with the detachable water pipe, and a front water pipeline is formed in an annular body part of the guide cavity body. A plurality of guide cooling water holes communicating with the front water pipeline are formed in the inner wall of the annular body part, and the guide cavity body is cooled by cooling water flowing out of the guide cooling water holes. The detachable dedusting nozzle is installed below a back water pipeline and used for spraying water to remove dust. According to the guide device with the cooling and dedusting functions, the guide cavity body and the stretching installing part are regarded as an installation basis, dedusting is conducted through the detachable dedusting nozzle, and cooling is conducted through the sprayed water of the guide cooling water holes; and the guide device with the cooling and dedusting functions has the good cooling effect and the good dedusting effect at a steel billet blooming outlet.