Here I am using Space() function as below:

select space(51) as Name, SEQ into #Temp from Member.

In the above query it is inserting space(1) instead of 51 spaces.

Can any one help me out in the same?

Thanks in advance!!

That is because the target table is created with a varchar column
instead use:
select convert(char(50),'') as Name, SEQ into #Temp from Member