The invention provides a dog MSC exosome preparation and a preparing method thereof. The preparing method includes: preparing exosome-free fetal calf serum, and separating dog MSC exosome. The preparing method has the advantages that the extracted exosome of the dog MSC exosome preparation prepared by the method is small in size, can easily achieve in-vivo circulation and can easily reach woundedtissue; in-vivo dosage stability can be guaranteed by directly using the exosome, the treatment effect is guaranteed to a certain degree, the exosome is free of toxic and side effects, and a foundation is laid for large-scale clinical application; the prepared preparation is applicable to dog experiment models, the dog MSC exosome preparation for treating skin injury is prepared, a dog skin woundcan be repaired by injecting the preparation to the periphery of the wound or directly applying the preparation to the wound surface, inflammation can be inhibited, healing can be accelerated, and scar formation can be reduced.