Scientific writing is essential for students to express their idea and to report their research. Problem-based learning model directs students to solve problems and report them in the form of scientific articles. The report is written logically and systematically. The research used a quasi-experiment method with 62 students as participants. The research was conducted in the Geography Education Program of Kanjuruhan University of Malang, Indonesia, academic year 2017/2018 on the course of Geography Natural Resource. The instruments used were essay tests and assessment rubrics for scientific writing. Data from problem-solving and scientific writing assessments were analysed with the Mann-Whitney test with a significance level of 5% after a prerequisite test. The results of the study showed that: problem-based learning model has a significant effect on students' problem-solving skills, scientific writing skill, and together problem-based learning and problem-solving skills had significant effect scientific writing skill.