The automatic modeling method and a classifier for OLAP data model includes acquiring a SQL query statement; parsing the SQL query statement and judging whether any syntax error or lexical error exists in the SQL query statement; extracting query structures from the SQL query statement to obtain at least N sets of query patterns, if no syntax error or lexical error exists; classifying the at least N sets of query patterns; merging the query patterns in each class to obtain a corresponding pattern relation tree; and converting the pattern relation tree into a corresponding data model. The classifier includes a static rule classification module, and a statistical rule and preset learning rule classification module. A data model generated with the method and classifier provided in the present invention supports all inputted SQL query statements and has certain generic capabilities to full support Cube operations and quick queries.