Virtual painting technology is a new technical means of modern art creation. 3D painting is a branch of virtual reality art. It uses computers or other intelligent computing devices to simulate the virtual 3D space environment, so that art creators can immerse themselves in painting creation. The difference between 3D painting and traditional painting is that it is a painting space from two-dimensional to three-dimensional. It is a painting creation process of double immersion of human brain and limbs. We believe that the artistic exploration of 3D painting is helpful to the improvement of painting artistic creation ideas and the expansion of skills. It is an embodiment of enriching the media and visualization of painting. Due to the complexity of 3D painting, this paper creates a cloud platform based on the high-speed and large storage characteristics of cloud computing, which will provide more efficient and convenient experience for 3D painting users. The key to the development of the cloud platform is to build an NX digital modeling and display platform based on cloud computing. Through the compression, serialization and network transmission of the three-dimensional image technology at the NX end, the three-dimensional model is finally displayed in the browser interface, and the basic functions of interacting with the model are provided for users, Cloud computing technology is used to arrange the computing work of 3D model compression into subsequent computing, which greatly reduces the redundancy of users' work. Through the research of cloud computing, this paper applies it to computer image technology, which makes the application of 3D painting flourish.