The study objectives are 1) to explain the effect of learning strategies based on investigation to critical thinking skills, metacognition, and mastery of the concepts at senior high school students; 2) to empower critical thinking skills and metacognition at senior high school students; and 3) to compare the level of the concept mastery of buffer solution chemistry between students who are taught based on the investigation learning and conventional learning. The methods used are preliminary observation, preparation of learning tools, development and verification of learning tools, trial and dissemination, pre-non-test, and implementing of chemistry learning tools based on investigation learning for senior high schools. The subjects of this study were senior high school students in Makassar city and Maros district. Learning tools are used in this study are Planning of Learning Implementation on Investigation Worksheets, a book of the investigation model, and the non-test also test Instruments for the Chemistry subjects of eleven grade of Senior High School. The research used was the pretest-posttest control group design. The results showed that firstly, there is an effect of the chemistry learning strategies based on the investigation to critical thinking skills, metacognition, and the concept mastery of senior high school students. Secondary the critical thinking skills and metacognition of senior high school students are empowered which is characterized by increasing critical thinking skills and metacognition of students after the learning process, and thirdly the level of the concept mastery of buffer solution chemistry of students who are taught by investigation learning is higher than conventional learning.