Abstract: A modified symbolic coded algorithm (MSCA) for generating symbolic network functions of analog circuits is presented.Comparing with original symbolic coded algorithm (SCA),the new algorithm has simpler coded cell and more accurate definition for coded theorem.So,MSCA can obviously improve computation efficiency and enlarge application ranges.Based on the MSCA,a symbolic network function simulator for analog circuits (SNSAC) is implemented.The main characteristics and construction of the program are introduced.Finally,two application examples for the analog circuits are given.