英语一个句子结构不明白？

that后面是主语。
这句话是it做形式主语。
正序应该是Had made her famous was not her success at university.
在大学里她除名并不代表她成功。

这是个强调句型。
that指的是her success,是that had made her famous的主语。
had 是谓语的一部分，帮助构成过去完成时，当然不能去掉。
如果你问的是that可不可以去掉，回答是也不可以，因为强调句中that是必须的。

it is...that。。。这是强调句型
HAD MADE 过去完成时。
HAD 去掉也可以，意思大致相同。