Name the blind son of Shiv ji?

According to the stories found in some Puranic texts, Lord Shiva and Goddess Parvati had a son named Andhaka. Andhaka was born blind (the name "Andhaka" itself means "the blind one"). He was created from a drop of sweat of Parvati or, in some versions, from the union of Shiva and Parvati under special circumstances. Andhaka is known in the Puranas as a powerful asura (demon) who was ultimately slain by Lord Shiva when he became arrogant and tried to seize Parvati.

So, the blind son of Lord Shiva is Andhaka.