This is a qualitative discriptive research to find common error on students writing. The research was conducted on june 23rd and 26th November '09. The instrument was students' writing which was taken by asking students describe a picture in a form of description. The method of the research was a descriptive research. It describes and interprets the exact data. The respondent of the research was the first grade students of secretary class. This study was a non-experimental study. It referred to the approach of error analysis. The procedures of it included recognition of error, recontruction of error, and explanation of error. The research activities were making the intruction to describe a picture, analyzing the errors, which were in the sample and revising the writing errors. The scope and limitation of the research was on grammatical aspects based on betty scrampfer azar guide line of writing. The guide lines were singular-plural word form, word choice, verb tense, add a word, omit a word, word order, incomplete sentece, spelling, punctuation, capitalization, article, meaning not clear, run-on sentence. The result of the research revealed that common error on the students ability were the error of verb tense is 40.15 %, word choice is 24.81%, singular-plural is 14.59%, add a word is 6.57%, word form is 5.11%, incomplete sentence is 3.65%, capitalization is 2.19%, article is 1.46% and word order is 1.46%.