Visual simulation of root system growth, an important approach to analyze the root system growth mechanism affected by the surrounding environment, is a significant task in the fields of computer graphics and botanical research, especially in agriculture and forestry. A modeling approach was presented to simulate the interaction between root system growth and the environment. This approach was dominated by the interaction of the root tips with the environment, and regulated by an internal resource allocation mechanism. Firstly, the nutrients absorbed by each root tip were calculated, and then the elongation rate and lateral root density of the root tip were regulated through internal resource allocation mechanism and the scaling function of environmental influence, while adjusting the growth direction of the root tip in real time by considering the blocking factors of the tropisms and obstacles. In addition, the approach provided several ways to control the shape of a root stem and its overall morphology of the root system, including editing the template curve, setting resource allocation weights and directional weights, etc. In the experiments, the root systems of different species were firstly simulated, followed by simulations of root systems in different soil environments, including various nutrient distributions and the influence of obstacles and pot walls. The results showed that the proposed approach had the ability to generalize the realistic models for multiple types of root systems for plants, while effectively representing a reasonable interaction response with the environment in a real-time way.