When you compare two of the computers,this is the more expensive one.请问句子通顺吗?

你是不是想表达：“比较一下这两台电脑,这一台更贵一点”?英语不是这么说的,这是标准的中式英语.更好一点的表达可以这么说：When comparing these two computers, this one is much more expensive.

再加一个one就对了 This is the more expensive one of the two computers

This is the more expensive of the two comparing with the computers. 这句话表达就有错误,而且容易产生歧义.compare表示比较,compare with sth. 表示同···作比较,而且必须是同一类.如果你用comparing 则表示比较的主体是主动的,而电脑则是被比较的.要么你就把with去掉,要么就改成Compared with these computers, this is the more expensive one of the two.