The invention provides a method and a system for showing a report form with non-fixed column numbers. The method comprises steps as follows: A, all column data of related report forms are acquired from a database according to an inquiry condition to form candidate columns; B, a first report form is created according to the candidate columns when no temporary report form identical to the candidate columns exists in the database; C, data inquiry is performed, the first report form is filled in, and the final report form is generated. The problem of uncertainty of the number of to-be-shown columns of the report form is effectively solved through arrangement of an extra temporary report form and according to creation and judgment ways of the extra temporary report form, report forms with different column numbers can be output according to different inquiry conditions, and the management of enterprise operation is further facilitated.