Emerged weed species and seasonal variations in emergences of selected 22 weeds were examined at 366 fields of 27 University's attached farms, which were upland crop fields, orchards and grasslands under ordinary crop management practices. As a result 4153 weed emergence data were recorded and emergences of 274 weed species were observed. And 1458 data were obtained in the examination of seasonal variations of weeds emergences. A relational database was made based on the store of the data. Finally the query program for users unfamiliar with usage of database was developed and installed on the database. This function enables the users to set a complicated query condition with easy operations. It is also possible to narrow down a data after an application of the query by a filtering function provided by the developed program In addition printing and data transfer functions are installed in the program for further data analysis.