Abstract: This paper presents a new method for triangulation of implicit surfaces. Particle system with normal constraint is used for sampling on the given implicit surface to get steady and reasonable sample particles. Two normal added vertices are introduced by extending the particle to an equal distance along the normal vector and the anti-normal vector. We generate tetrahedral mesh with the sample particles and the normal added vertices, and remove the normal added vertices and corresponding edges to obtain the final triangular mesh. Experiments are reported to demonstrate the efficiency of the new methods.