In this paper, the deep generative model and stochastic backpropagation method are used to innovate the modern landscape garden design, and at the same time, traditional cultural elements are integrated in the design process. By constructing generative adversarial networks and utilizing diffusion models, this study improves the diversity of design samples and enhances the display of cultural flavor. The comprehensive evaluation test shows that the modern landscape garden integrating traditional cultural elements exceeds the mean value in 17 evaluation indexes, especially the value of the evaluation factor of artistic flavor display reaches 0.0476, which is 460% higher than the mean value. The survey of tourists shows that the overall evaluation score of modern landscape garden is 76.4015, and the evaluation grade reaches “good”, which effectively verifies the practicality and effect of the design method of this paper.