▲这是一个很有趣的问题，看似简单，但好像又没有定论。我查了一些资料，查得的结果是：用不用定冠词均可，但似乎不用定冠词更普通。

1. 不用定冠词的实例：

(1) It is five years now since I graduated from No. 3 High School. 我从三中毕业已有5年时间了。(2008全国卷I改错题，此处无错)

(2) After that I went to No.62 Middle School of Dalianand graduated this summer. 后来，我上了大连第62中学，并于今年秋天毕业。(1996全国卷书面表达“标准范文”)

2. 用定冠词的实例：

the No. 26 Middle School第26中学（《薄冰高级英语语法》）

有趣的是，上面一例出自《薄冰高级英语语法》第3.8节，本节专门用于论述“定冠词用于专有名词”的用法原文如下：

（定冠词）表学校名称，多含普通名词，表零念，如：

the No. 26 Middle School第二十六中学

the Snedeker School  斯内德克学校

the Railway Primary School  铁路小学

the Chinese People’s University 中国人民大学

the Beijing Medical College  北京医学院

the Central Academy of Fine Arts 中央美术学院

the University of London  伦敦大学

the University of Chicago  芝加哥大学

the College of Idaho  爱达荷学院

the School for International Training  国际训练学校

▲查了一下China Daily（中国日报），基本上不用冠词，但偶尔也见到有用定冠词的。

1. 不用定冠词的实例：

(1) Parents watch as their children begin military training under the scorching sun at No 1 Middle School in Shijiazhuang, North China's Hebei province, Aug 26.（《中国日报》2014-08-27）

(2) Starting this year, the department has also been cooperating with Beijing No 11 Middle School.（《中国日报》2014-07-08）

(3) On May 26, music researchers and teachers from cities of Karamay, Changji and Tacheng gathered at No.7 high school in Karamay to share their ideas and experience on art performance. （《中国日报》2014-07-04）

(4) On the day, teachers and students from No.1 high school, No.5 high school, No.6 high school and Karamay Senior High Schoolper formed some music programs.（《中国日报》2014-07-04）

(5) Students prepare for the gaokao, China’s national university entrance exam, at No 2 Middle School in Nanchang, the capital of Jiangxi province. （《中国日报》2014-06-06）

(6) Also, Karamay No.1 Middle School introduced a comprehensive and advanced management and curriculum system of Beijing No.4 High School, which helped cut the drop-out rate and recruit many outstanding students from surrounding areas. （《中国日报》2014-06-27）

2. 用定冠词的实例：

(1) Teachers from the Linfen No 3 Middle School will start teaching the students senior high school courses at Red Ribbon after Sept 1, he said.（《中国日报》2014-07-14）

(2) Several of my students here in Zhengzhou at the No. 19 Middle School (I teach some classes in their International High School) got to go to the U.S. this summer on a trip organized by the school. （《中国日报》2014-09-03）