An information monitoring and updating method and system for a transport stream is provided. First, a transport stream is received. The transport stream includes a program specific information (PSI) table, and the PSI table is divided into a plurality of sections. Next, by setting a first filtering parameter of a monitor-section filter, the header of each section of the PSI table is filtered out and is then checked whether to be a latest version or not. When all the section headers of the PSI table are of the latest version, each section of the PSI table is filtered by setting a second filtering parameter of a table-section filter.