Most of requirements were analysysed in the morning, I've done some things. 1. Create a table in my DB. 2. understanding how google Calendar can do. 3. makeing sure steps of construction. Google Calendar can create many events in the same time. It sounds a good news for me. However, if you shared it with friend and choose " managing and editing ", Calendar owner could not restrict friend delete or modify this Calendar. So, I constructed a Account table in my DB, use php to restrict Users. Maybe it is a stupid way, but it was a only way that i could do. last 3 days, Cheer up!