Like mentioned make sure you are logged in on both devices to the same Apple ID and calendar.
Also I would try this on the iPhone goto calendar.app. Then at the bottom in the middle it says "Calendar", click that. From that screen make sure the calendars you want to show are checked. Once you are certain they are pull down on that screen so it refreshes. Then check your calendar to see if the stuff from the Mac is now on the phone.
My calendar will not sync with my iPhone or iPad unless I manually refresh it for some reason.