This research aimed to identify whether the use of Mind Mapping was effective to improve the students’ writing ability in writing descriptive text. The method of this research was quasi experiment. The total sample was 62 respondents. The sample was divided into control and experiment class. In collecting data, the writer used test as instrument and was administered twice. This research used quantitative method which the data was served by numerical and tested by statistical formula or t-test. When analyzing the data obtained, it was found that t-test result was 4.920, while t-table score at significance level of ɑ = 0.05 for df (degree of freedom); 60 was 1.67065. It means that the hypothesis which stated that mind mapping was effective to teach writing of a descriptive text at the seventh grade students of SMP Negeri 1 Baturaden Purwokerto in the academic year of 2017/2018 was accepted.