区别就是两者词性是不一样,具体的不同如下
over表结束了是形容词
finish是动词,但be over=finish,中文意思是结束,完成了。
例如
Our budding romance was over.我们刚刚萌发的浪漫爱情结束了。
=Our budding romance finished 
我们到达时,会议已经结束了。By the time we arrived the meeting was over.
怎么区别over和finish
over 与finish(结束……)
over作此意讲一般是副词,前面必须有动词才能做谓语,一般结构是be over. 例如:School is over, I went straight home.
而finish是动词,后面接名词或动词的ing形式。例如:
I finished my homework, I went to bed.
或I finished doing my homework, I went to bed.