The abstraction process of the y=kx linear equation of two sixth grade students, who have upper level success in mathematics, has been researched by using RBC+C abstraction model. Firstly, research and application problems have been prepared in form, which would allow distinguishing, recognizing, building-with, construction and consolidation cognitive activities with this aim. Prepared problems have been presented to the student group that constituted of two students during the applications and it has been provided that the students worked together on these problems. It has been examined through two different applications, which were performed at different times, whether the students have constructed the y=kx linear equation of themselves, or not. Besides, their situation of recognizing and using the required preliminary knowledge during the abstraction process has been investigated. In conclusion, it has been understood that both of the students could recognize and build-with the preliminary knowledge, which is required for construction of the y=kx linear equation and that they have constructed the y=kx linear equation of themselves.