You aren't checking for @@Transcount in your code. Also, you should use a try catch block and return after the error.

Create Procedure One as

declare @ErrorMessage varchar(300)

Begin Tran

begin try

exec two

end try

begin catch

if @@Transcount > 0

Rollback Tran

select @ErrorMessage = Error_Messate()

Raiserror (@ErrorMessage, 16,-1);

return

end catch

if @@Transcount > 0

Commit tran

go

Create Procedure two as

declare @ErrorMessage varchar(300)

Begin Tran

begin try

Update some tables

end try

Begin catch

if @@Transcount > 0

Rollback Tran

select @ErrorMessage = Error_Messate()

Raiserror (@ErrorMessage, 16,-1);

return

End catch

if @@Transcount > 0

Commit tran

go