Thanks RK.
But i already checked backorder to “not allow” in woocommerce. not allow is my default value for all of my shop products.
This problem is related to manual orders in admin level. When i create a new order with admin right in admin panel (not in foreground of my website), woocoomerce let me to add a product with 0 stock, and when i create order, woocommerce will change stock from 0 to -1 !
