The concept of chemistry which is microscopic and macroscopic causes the students of SMAN 1 Pringgasela to have difficulty understanding the concept, in addition to the weak learning process where the teacher uses the lecture and discussion method more often, and the teacher never measures students' science process skills. So that the learning outcomes obtained are less than the KKM. For this reason, the researcher applies a guided inquiry learning model with a contextual approach that aims to improve science process skills and student learning outcomes on the buffer solution material. This research was conducted at SMAN 1 Pringgasela, East Lombok district. This type of research is a quasi-experimental research design with post-test only control group. The population in this study were all students of class XI IPA at SMAN 1 Pringgasela which were designed by 60 students who were all used as samples, with details of class XI IPA 1 which was designed by 30 students as an experimental class and class XI IPA 2 which included 30 students as the selected control class. randomly clustered. There are two types of data collected in this study, namely, the process of data skills obtained from the results of the buffer solution practicum using observation sheets and data on student learning outcomes using objective tests. The data analysis used was in the form of an independent sample t-test. The results showed that the results of data analysis of science process skills and student learning outcomes on the buffer solution material obtained a significance level smaller than the predetermined significance level. So it shows that there is a significant difference in the average score of posttest science process skills and learning outcomes between the experimental class or the control class.