am trying to import sales orders for different customers with more than sales order line it gaave me this error 

Missing required value for the field 'Order Reference' (name)

any value i set it refuse it 

From the FREQUENTLY ASKED QUESTIONS section of the Import screen:

How can I import a one2many relationship (e.g. several Order Lines of a Sales Order)?

If you want to import sales order having several order lines; for each order line, you need to reserve a specific row in the CSV file. The first order line will be imported on the same row as the information relative to order. Any additional lines will need an addtional row that does not have any information in the fields relative to the order.

As an example, here is a sample CSV file of some quotations you can import, based on demo data.

Ref,Supplier,Destination,Pricelist,Order Lines / Product,Order Lines / Quantity
PO000020,ASUSTeK,Stock,Default Purchase Pricelist,ADPT,20
,,,,CARD,30
,,,,C-Case,40
PO00002,Axelor,Stock,Default Purchase Pricelist,CD,5
,,,,CPUa8,15

This file imports TWO quotes, the first having THREE lines, the second having TWO lines.

To import From CSV,You can Check HERE   

Example for importing sales order:

Reference/Description,Customer,Order Lines / Product,Order Lines / Quantity
PO000020,ASUSTeK,ADPT,20
,,CARD,30
,,C-Case,40
PO00002,Axelor,CD,5
,,CPUa8,15