I want to take Revit file to QGIS via FME converter. But the coordinate system doesn't fit. So I want to find a solution. Thank you.

If there is some sort of standard coordinate system used in the Revit file, you can use e.g. the CsMapReprojector or similar, depending on your coordinate systems.

If the Revit file is in an unknown, local coordinate system you can use the AffineWarper to transform the data.