My signature work project is to explore the asymptotic tumor boundary problem with a necrotic core, by establishing a mathematical model to simulate its growth. It is simplified from a partial differential equation system to an ordinary differential equation system by assuming the tumor as a regular sphere. Through using the Modified Bessel function of the first kind and the second kind, the solution to the ODEs can be obtained. After plugging the boundary conditions into the solution, six equations are obtained with the aim of finding their root. Then, Newton’s method in six dimensions is applied to generate a numerical solution. With a numerical root, the growth trend and the characteristics of the tumor can be studied.