Create a sample table with an identity column in it.

Create table [order_details]
(
OrderId int identity,
OrderName varchar(10),
UnitPrice int
)

Select ColumnProperty(Object_id('order_details'), 'OrderId', 'IsIdentity')

Declare @colName varchar(100)
Declare @RetColName varchar(100)

Set @colName = 'OrderId' -- Specify the column name for which you want to check

--Status column = 128 means its an identity column
Select @RetColName=[name] from syscolumns where (status & 128) = 128 and id=(select id
from sysobjects where name='order_details')

If @colName = @RetColName
Print 'Its Identity'
Else
Print 'Not an identity column'