on behalf是代表的意思，一般后都是加of，表示代表谁，所以on behalf of是固定搭配。
音标：英 [ɔn biˈhɑ:f ɔv] 美 [ɑn bɪˈhæf ʌv]
释义：为了…的利益;代表…
1、On behalf of the staff, I wish to extend our warmest welcome to you.
我谨代表全体职工，向你们表示热烈的欢迎。
2、I'm collecting on behalf of the blind.
我正在为盲人进行募捐。
3、He gave witness on behalf of an accused person.
他为被告作证。
4、A lawyer acts on behalf of his client.
律师作为当事人的代言人。
5、I shall appreciate it as a personal favour ( said when making a request on behalf of a friend).
我将感同身受。