Based on a microcomputer installed with the Linux operating system and integrated with the intranet environment, the Blast software with the WEB interface was constructed for visualized sequence similarity analyze. All of the users in the intranet could visit the WEB Blast server using WEB-browser to analysis their sequence easily. The databases to be searched might be either the public database such as EMBL or GenBank nucleic acid sequence database and SwissProt amino acid sequence database or the private sequence databases prepared by themselves. Result demonstrated that this intranet WEB Blast environment is very useful in large-scale nucleic acid sequences and amino acid sequences analysis.