它們的區別是有沒有一個定冠詞,意義也不一樣
in honor of 的意思是為了紀念…,向…表示敬意。
例如:we have built a monument in honor of our heroes who died for the good of our society.
我們建造了一座紀念碑以緬懷那些為人民的利益而犧牲的英雄
in the honor of :以…的名義。
例如:I am calling for you to protect our campus in the honor of the student Union.
英語中,有定冠詞the與沒有定冠詞the的意義有區別的短語還有 
in front of:在…前面
she sits in front of me
她坐在我前面
in the front of:在…前部
the teacher is standing in the front of the class room
老師站在教室前
in charge of :管理…
he is in charge of the firm
他管理那家商行
in the charge of:在…的管理之下
the firm is in the charge of him
那家商行又他管理
go to school:上學
he went to school on weekdays
他平時去上學
go to the school:去學校
The teacher went to school earlier 老師早早去學校
in honor of 的意思是紀念,向某某表達敬意。in the honor 的意思是以某某的名義。基本上兩個短語是有着意義的不同的。