English is important for student of Thailand because English language is formal to communication and its international language. But the students have little knowledge, especially written English sentences. We saw this problem and want to know about the mistake, there are many problems of writing in English subject such as; pattern writing, singular/plural Form, word choice, preposition, word order, article, spelling, capitalization , wrong/misused word, missing word, and Redundancy. These problems are basic skills of students. It’s different and some teacher may be teaching imperfectly in the past. So we need to study about these problems for resolve it