Is GUID(uniqueidentifier) not suitable for a clustered index? When i use uniqueidentifier datatype for primary key column then it will automatically create clustered index...
So, will it slow down my queries or not ?

I am explaining some description of my problem..
I have two publisher which is replicating data into one subscriber(i.e primary Alwayson) then how to maintain primary key value in this scenario ?

So,Please give me a idea to maintain primary key value ?
It will slow down inserts rather than queries. That's because it is essentially inserting a record somewhere randomly inside the existing records, instead of just whacking it on the end (as it would if you were using an identity or sequential dates).

You can somewhat reduce this by using NEWSEQUENTIALID instead of NEWID (assuming the GUID is generated by the database rather than your application).