This research aims to find out whether there is a correlation between vocabulary mastery (X) and students' descriptive writing skills (Y) class X.2 at SMAN 4 Palangka Raya. The research method is a quantitative, correlational research design. Using random sampling so that the class chosen is X.2. Data collection tools use tests. Data were analyzed using simple linear regression. Based on research results. The average student test score was 82.07 for vocabulary mastery and an average score of 67.69 for descriptive writing skills. The research results show that there is no correlation between vocabulary mastery and students' descriptive writing skills, with a correlation significance of 0.744 which is greater than 0.05 (probability value) which means H0 is accepted while Ha is rejected. The correlation value (R) is 0.063 and the R square value is 0.004, which means the influence of variables X and Y is 0.4%. So it can be concluded that there is no correlation between vocabulary mastery and students' descriptive writing skills.