It's means a business which is owned and run by a wife (mama/mother) and her husband (papa/father).
Thanks so much for your reply!
Just now,I came across(tell me how to express this in another way,I am nearly fed up with "come across",thanks) another phrase with operation in it which reminds me of this 'mama-and-papa operation".The latter one is from an interpretation book complied by some my natives.And I doubt that foreigners also say it like that.
Thanks again for your help!
help me vary my expression of 'come across"please;thanks.