The invention discloses a potassium silicate paint added with hydroxyl silsesquioxane and a preparation method thereof. The paint is prepared from the following raw materials in parts by weight: 80-120 parts of liquid potassium silicate, 1-15 parts of zinc powder, 3-20 parts of an aqueous solution of aluminum tripolyphosphate with the concentration of 10%, 5-20 parts of hydroxyl silsesquioxane, and 10-500 parts of water. The preparation method comprises the following steps: firstly, weighing the components of the zinc powder, the aqueous solution of the aluminum tripolyphosphate with the concentration of 10% and the hydroxyl silsesquioxane according to proportion, putting the components in a ball milling jar, and performing ball milling on the components in the ball milling jar for 1-2 hours at the rotating speed of 250-350rpm to obtain a component 2 for use; weighing the potassium silicate according to the proportion, using the weighed potassium silicate as a component 1, stirring the standby component 2 and adding the standby component 2 to the potassium silicate of the component 1 at the same time, and sufficiently mixing the component 1 and the component 2 to obtain a mixture; adding water to the obtained mixture, stirring the mixture in a stirrer for 5-20 minutes at the rotating speed of 250-350rpm, and filtering the stirred mixture through a 200-mesh screen stencil to obtain the paint. The paint has the benefits of no toxicity, no corruption and environmental protection.