A person is engaged in share business.Under which head of Accounts, should I creat each category of Share Purchased i.e... under Current Asset or Stock of Inventory?

What entry should I pass while selling of that share for profit or Loss?

Stock of Inventory is NOT a recognised heading. It comes under Current Assets
Itself.
To answer your question, Share Purchases
Can have its own heading called INVESTMENTS.
However, it can be put under Current Assets
As well.