我父母自已写个statement 说从未参加过共产党？-Right. Just like when a person plans to get married, he just needs to declare he is single at that time and thus, he is qualifed to marry the girl.
不用原单位或公安局什么的出证明？
但好像移民局明确要求要公证书。原文是：Please provid a notarized statement explaining if you were you ever a member of the Chinese Communist Part.
-That means that if you joined the Party, then you need to provide that document. Because your parents have never join the Party, how are they able to provide that? "you were ever a member of the Chinese Communist Party" means you joined the Party before.
