I want to override "PrintProducts" method in pdfservice class,which is in Nop.services project.
Is it possible to override it in my plugin without touching base code.
It is a public virtual function so yes you can
protected override void PrintProducts(int vendorId, Language lang, Font titleFont, Document doc, Font font, Font attributesFont)
Or alternatively if you just want to print the Products report from a button on a .cshtml page in your plugin then no need to override you can just call your plugins PrintProducts routine