说明文的写作相对于论说文来说，有一定的套路可循，因此不是十分复杂。说明科技方面的内容常用定义法、比较对比法、分类法、因果法等；说明自然环境方面的内容常用时间次序法、分类法等。当然，随着对象的不同，具体应该采用的方法也会有所不同。
说明文的写作应该注意的事项有下面几点：
1.语言简明扼要，通俗易懂，避免夸张华丽的辞藻，要把真实的一面展现在读者面前。
2.说明时一定要把握一个中心主题。说明文中细枝末节较多，但不能喧宾夺主。
3.说明的次序非常重要。合理的次序会使文章条理清楚，脉络明晰。因此，练习时可以尝试不同的次序进行写作，找出最合理的一种。
4.由于说明文写实性较强，有时难免会让人感到没有生气。因此，可以适当使用一些比喻、拟人等修辞手段，来增加文章的色彩。
下面是一篇说明一所医院布局的文章。文章虽短，但需要说明的内容却达11处之多。平均一句话就要描写一处，如果组织得不好，便会给人凌乱的感觉。
为了避免这一点，文章把整个布局图分三部分来写：
贯彻医院的是main road，第一部分以大门为参照物，介绍了靠大门且通过main road东西相对的急诊楼和门诊楼。
第二部分以湖为参照物，中心线还是main road，介绍其他分诊楼、实验室、放射室等。
第三部分写main road尽头的建筑物。
这样，繁多的细节显得井井有条。因此，选择好主线及参照物是决定文章成功的关键。
Directions：For this part，you are allowed 30 minutes to write a composition about“THE LAYOUT OF A HOSPITAL”. Locate some important departments in the hospital based on the information given below.Your composition should be no less than 120 words.
（1）the Emergency Department
（2）the Out-patient Department
（3）the Surgery Department
（4）the Dispensary
（5）the Physician Department
（6）the Eye，Ear，and Throat Department
（7）the Dental Department
（8）the Laboratory
（9）the X-ray Department
（10）the Administrative Building
（11）the Ward
例文：
The Layout of a Hospital Near the gate，on the westside of the road is the Emergency Department. Opposite the Emergency Department across the Main Road is the Out-patient Department. The building to the southwest of the lake is the Dispensary，which face the Surgery Department lying on the other side of the road.Along the west wall，from south to north，stand three buildings：the Physician Department，the Eye，Ear，and Throat Department，and the Dental Department.
The Laboratory is to the northwest of the round about，and beside the Laboratory，the X-ray Department is located on the same side of the road. A winding road by the lake leads to the Ward.
Near the end of the Main Road，the Administrative Building is situated on the east side.The hospital is nicely and conveniently laid out.
