Checking whether a table exists in a Microsoft SQL Server
database is easy. You can use this query: 

SELECT 'x'
FROM sysobjects
WHERE type = 'U' and NAME = 'mytable'
But this query will not work while searching for global
temporary tables. Global temporary tables are stored in tempdb. 
Use this syntax for the search: 

DECLARE @temp_table VARCHAR(100)
SET @temp_table = '##my_temp_table'
IF NOT EXISTS (SELECT 'x'
          FROM tempdb..sysobjects
          WHERE type = 'U' and NAME = @temp_table)
    PRINT 'temp table ' + @temp_table + ' does not exist'

ELSE
    PRINT 'temp table ' + @temp_table + ' exists.'
Note: You cannot search for local temporary tables (# prefix
tables) in this way. This is because SQL Server appends a
unique number to the name you supply. For example, if you
specified "#temp," the name in sysobjects would be something
like "#temp____1234." 

use tempdb

sp_tables '##%'