In order to optimize the calculation method of navigable width of channel in current code，a new analysis method based on AIS big data is proposed with corresponding software developed. Such program consists of relational database，CAD visualization technology，mathematical fitting algorithm，etc. As a result，it makes AIS big data fast analysis achievable by solving the defects，like massive raw data problem，data filtering difficulty，low resolving efficiency and so on，which in turn provides solid data support for navigable width calculation. Within the program，C#.Net is selected with UI framework WPF and SQLite database to jointly develop. Moreover，the research achievements have been utilized in the second phase of Lianyungang 300，000 DWT navigation engineering and yields good results，which have a reference significance for other projects using AIS bigdata for certain purposes.