With the development of computer technology, digital painting has become more and more mature, which makes the whole creative process of painting more convenient, efficient, and diversified. This paper first introduces the definition, development history, and application of digital painting. A computerized painting model is created using knowledge representation, and the basic unit of the painting model is described. The paintbrush consists of hair filaments, each of which has its color tone and strokes. The brush’s movements are a result of position, pressure, and color tone, while the picture is a collection of strokes. Geometric transformations such as translation, rotation, and scaling are applied to the geometric information describing the strokes. This approach enables the simulation of painting effects, including the creation of scratches, color diffusion effects, texture mapping, and mutations on the strokes. This paper’s model enhances the painting skills of art students in six dimensions, achieving an efficiency evaluation score of 93 and a quality evaluation score of 96 in the abstract painting style. This model meets the realistic requirements for the advancement of computer-aided painting technology in art creation at a high level.