The invention discloses a cold-spraying zinc surface sealing agent and a preparation method thereof. The cold-spraying zinc surface sealing agent is prepared from the following components in parts by weight: 5-10 parts of attapulgite clay powder, 2-3 parts of sodium based bentonite, 10-15 parts of aluminum powder, 10-15 parts of thermoplastic resin, 5-10 parts of acrylic resin, 4-5 parts of methyl cellulose, 4-5 parts of dispersible latex and 20-35 parts of ethanol. A preparation process of the cold-spraying zinc surface sealing agent is simple; and the prepared cold-spraying zinc surface sealing agent can be used for remarkably inhibiting a bubbling phenomenon caused by the fact that the sealing agent is sprayed after cold-spraying zinc is sprayed.