Computational thinking is viewed as a critical and necessary skill in the 21st century that everyone should learn. In addition, six years ago, Wing had argued for adding this new competency to every child's analytical ability as a vital element of science, technology, engineering, and mathematics (STEM) learning. This study aims to analyze an unplugged computer course effects on young students' computational thinking, especially focuses on their programming attitude and computational concepts and explore the relationship between logical reasoning ability and computational concept. This study investigates the development of 25 young students' computational thinking in 1st to 2nd grade through a "computer science unplugged course", which is a curriculum that has been developed for many years and has the goal to teach computational thinking without using computers. It adopted action research and collected data through questionnaire. The results showed that there is a strong connection between logical reasoning ability and computing concept. Moreover, there was little difference in the attitude toward programming between gender in young students.