This research departs from the learning student outcomes in the fourth grade of elementary school state Balasklumprik I/434 Surabaya, which is below average completness minimum criteria (CMC). This research want to prove how the student activities, teacher activities and students outcome if learning use writing a private journal with step by step. This experiment was conducted at Elementary School State Balasklumprik I/434 Surabaya particular fourth grade. This research was applied for 21 students in the class. The experiment method is classroom action researh (CAR). Data collection techniques used in this research is a form of observation technique and the asessment of teacher activity during the learning activities of students, asessment of student learning outcomes, student outcome data and writing technical documentation in the form of photographs. While the data analysis techniques used in this research is the technique of qualitative and quantitative data analysis. From the analysis of the data showed a signifikan effect. It can be improved by the activities of student and teacher is getting better. Student learning outcomes also increased, we can see from the increasing average student scores increased from the 68,04 in the first cycle and 90,4 in the second cycle. Based on the learning outcomes achieved by students, it can be concluded that ‘The Improving of Narrative Expository Writing Skills Through Private Journal Students on Fourth Grade at SDN Balasklumprik I/434 Surabaya' has done well and achieved results exceding targets for targets classical completeness and Completeness Minimum Criteria (CMC).