A mediate software tool for access to a SQL database is applicable to a server for expanding the capacity of a SQL engine so as to service more people simultaneously. The mediate software tool comprises an access module and a SQL instruction dispatching/receiving module. The access module is arranged for building a plurality of SQL instruction accesses on a net between the server and a plurality of client computers, in which the built SQL instruction accesses are usable for transmitting/receiving a SQL instruction and the processed result thereof. The SQL instruction dispatching/receiving module is arranged for dispatching the SQL instructions in the SQL instruction accesses to the SQL engine for processing and for receiving the processed result and transmitting the same to the access module.