| Cyclotrons are not only widely used in fundamental researches in national defense, but also widely employed in isotopes production, medical diagnosis and proton therapy. By employing VP technology, we applied virtual method in design, production, installation, and simulation of low energy cyclotrons, which conduces to reducing cost and risks.The nonlinear space-charge field of a beam is a serious concern for beam emittance growth in particle accelerators. This effect is most pronounced when particles are slow and space-charge forces are significant. The general property of space-charge dominated beam behavior is that a beam with an initial nonlinear profile tends to become more uniform and this process is associated with strong emittance growth and the appearance of beam halo, therefore, describing the behavior of the beam with space charge effect is necessary, non-linear beam simulation system will be as an important component of the VP platform.This paper discusses the research and implementation of the non-linear beam simulation system with space charge effect. First of all, based on the Boundary Element. Method (BEM) theory, we obtain the computational expressions of space charge field in free space. Then, the analysis and design modules are introduced in details. Finally, the simulation platform is developed including five parts, namely, Beam distribution generator in phase space, pre-processing, distribution testing, simulation and post-processing.For validating the accuracy of the design, according to laminar flow, we obtained the formula of beam dynamics from specific cases and computed the approximate solution with initially K-V beam and Gaussian beam. The calculation shows good agreement between theory and numeric results. Finally, the simulation result of an injection beam line is presented. The computation results are compared with ORBIT and TRACE 3-D, which shows good agreement. This code can be used to study beam dynamics in linacs and high intensity cyclotrons.
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