Want to know details and meaning about the trace of SQL Server I referred to this article: sp_trace_setevent (Transact-SQL).

And trace my SQL Server on production machine for months.

EventId of most of the traces were: 10，12，14，17

The MSDN says:


10 RPC:Completed
12 SQL:BatchCompleted
14 Audit Login
17 ExistingConnection


Please tell me what do they mean in the performance perspective. Which ones should I keep an eye on and examine in detail. Or am I missing something. Thanks!
You appear to have setup a trace with no understanding of why you've done so. There is little point in running a trace for 10 minutes, let alone months, without a reason.


  Scenarios for using SQL Server Profiler 
  
  The first step in using SQL Server Profiler is to identify your
  reasons for monitoring an instance of SQL Server.


The most common scenarios (taken from the above link) which may be relevant to you are:


Find the worst-performing queries.
Monitor stored procedure performance.


A trace that captures RPC:Completed and SQL:BatchCompleted events (Stored Procedure and TSQL classes) with Duration, Reads and CPU data columns will provide you with a diagnostic log of how your queries are performing. You can import this trace file to a table and run queries against it to identify the slowest, highest IO or highest CPU consumers for example.

If you have direct access to the server and want to analyse performance, I'm inclined to suggest that you ignore profiler traces and start with the SQL 2005 Performance Dashboard Reports. When you've grasped the basic concepts of Troubleshooting Performance Problems, invest some time understanding Dynamic Management Views (DMVs) and how they can help with performance analysis.