This research aimed to implement microscale experiment and Inquiry Method to develop scientific thinking skills. The microscale experiment is an experimental method that requires very low amount of chemical substance approximately 0.05 – 1.0 g., and it reduces a leftover chemical substance which is an environmentally friendly method. Moreover, the microscale experimental method is very fast technique which helps students save time and have enough time to discuss further details regarding the lesson. The microscale experiment using in this research was Electrochemistry and Titration which consisted of 3 topics as follows; Galvanic Cell, Electrolysis and Acid-Base Titration. The Inquiry Method consists of 5 stages which are 1) Engagement Stage; which urges the students to interest and question, 2) Exploration Stage; which emphasizes the lecturer and students to plan and do the microscale experiment together, 3) Explanation Stage; which allows the students to plan and do the second microscale experiment by themselves, 4) Elaboration Stage; which allows the students to present the experimental results together, and 5) Evaluation Stage; which evaluates the students’ scientific thinking skills at the end of the experimental process. The learning evaluation and measurement tools were designed and divided into 5 categories; classification, categorization, conclusion, application, and prediction. The sample group was 59 engineering students, from King Mongkut’s University of Technology North Bangkok, who were divided into the control group of 30 students for the normal learning and standard experiment, and the sample group of 29 students for microscale experiment and Inquiry Method. The result found that the sample group had higher scientific thinking skills with the statistical significance of 0.1 and the sample group’s scores of developing scientific thinking skills was higher than the control one.