The similarities between the variety show, the evangelical meeting, and the party convention are striking.
why author has used coma after meeting in the above sentence?
Because the author is creating a list of three items.
Generally I had seen no coma before the 'and' but in some cases the author uses coma even after 'and', so this small details make me confuse
Ah yes, sorry, it's a style issue. This comma is known as the 'Oxford' comma. Some people do it and some people don't.
It is useful when the last two items of a list could be mistakenly linked together.