Earth Science System in the Community is a learning model relevant to the 2013 curriculum and can improve students' critical thinking ability. The research aims to determine the effect of EarthComm learning models assisted by Avenza Maps application on students critical thinking ability. This type of research is a quasi-experiment with a pretest-posttest control group design. The research was held at High School 2 Mojokerto in the even semester 2019/2020. Data analysis using Independent Sample T-Test with IBM SPSS Statistics 22 for Windows. The results showed there was quite a significant difference between the critical thinking ability of the experimental class and the control class, evidenced by the value gain a score of the experiment class (28.11) more significant than the control class (19.89). EarthComm learning model assisted by Avenza Maps application affecting the students critical thinking ability because the syntax of EarthComm invites students to observe directly in the field. Through direct observation, students can feel and understand what is happening in the field to improve students' critical thinking ability. Suggestions are given to (1) the teacher of Geography subjects, hopefully, able to implement EarthComm learning model assisted by Avanza Maps application about the Earth system material that demands critical thinking capabilities in it; (2) further researchers, it is advisable to replace or add other bonded variables