Maria Duran has been claiming ownership of part of the star since 2010 when she threatened to bill solar power users.
The 54-year-old registered the star in her name at a notary office in Spain, before opening an eBay account selling square-metre plots for one euro each.
But two years later eBay pulled her listings, saying they violated its intangible goods policy, and her account was blocked.
She threatened to sue, and now one Spanish court has recognized her claim.
A trial will take place next month, with Ms Duran demanding around £7,500 for payments she says she has not received.
Ms Duran, from Vigo in the Spanish region of Galicia, has rejected an attempt by eBay to settle the case out of court.
She continues to sell Sun plots on her own website.
She says while there is an international agreement which says no country can claim ownership of a planet or star, she is an individual and is not bound by the agreement.