According to the finite difference principle, a one-dimensional Schr\"{o}dinger equation can be converted into a set of nodal linear equations expressed in a matrix equation after the space is divided into a series of discrete nodes with an equal interval. The matrix left division command offered in the MATLAB software can be used to derive the function approximation of each unknown nodal function. This method is simple in concept, convenient in operation and can solve large linear equations without more efforts in programming.