English is important for student of Thailand because English language is formal to communication and its international language. 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 the basic skills of the students to learn to write in English sentences. So we need to study about these problems for resolve it.