how to convert autocad sheet format to solidworks sheet format??
It is a solid model?
I think the easiest option is to import the folded solid part into SolidWorks.
You can then use the "Convert to Sheet Metal" tool to detect the bend and tears.
From there you should have a sheet metal part in SolidWorks which can be flattened.
Obviously the success of this is going to be somewhat dependent on the complexity of the part, but it should get you started in the right direction.
I imported a piece in step and right click on the imported function then on featureworks recognize the functions. By checking all the sheet metal features ... select the fixed side ... chances are that all the sheet metal functions have been recognized.