The performance for background server is higher required for mobile terminal application software, compared to the requirements of performance for application software. This paper focuses on the research about script design method, which is used for performance test of mobile terminal application sever based on LoadRunner. Firstly it analyzes the problems of recording script directly based on LoadRunner, then proposes a packet capturing method for script design based on the tool of Fiddler. It is verified that the method can be used in the performance test of mobile terminal application sever based on LoadRunner efficiently by the practice result.