The invention discloses a preparation method of fruity bread sauce mainly prepared from oats. The preparation method comprises the following steps: firstly soaking the oats, then cooking the oats to be a mushy state, and then grinding the oats to form oat paste; adding amylase into the oat paste to perform the enzymolysis; adding comprehensive yeast, fermenting, and homogenizing; adding saccharosesyrup, vanilla extract, fructus lycii, longan pulp, coix seeds and table salt, sufficiently uniformly stirring, boiling with water, after partial water of the mixture is vaporized and the mixture isin a porridge-like semi-fluid state, stopping heating, and cooling to the room temperature; then adding mashed apple, mashed banana, lemon juice, and Cranberry juice, and uniformly stirring; homogenizing, then adding potassium sorbate and sodium benzoate, stirring, and uniformly mixing; and loading the mixture into a container, performing the pasteurization, heating the mixture for a period of time, and then cooling, thus obtaining the fruity bread sauce. The preparation method adopts the oats as the main material and utilizes natural beta glucose as a natural thickening agent, no food additive is added, and a finished product is good in thickness, stability and taste. The method is simple and easy in industrialized production.