AbstractThis paper presents a new method to determine the symbolic gain of a linear system via Mason's formula. A combined searching algorithm based on the breadth‐first and depth‐first searching algorithms in a directed graph is devised to find the forward paths and loops in the linear system. Mason's formula is then determined via touching‐non‐touching matches of forward paths and loops in the system. A SPICE‐like system Description language (SDL) is also proposed to describe the linear system so that this new algorithm can be put into execution in a computer language. In comparison with other approaches, this method is more straightforward and needs no complicated matrix operations. the completeness of this new method had already been guaranteed by Mason's original formula. It is also believed that Mason's formula has a new interpretation through this new approach.