Abstract: This research is intended to construct character structure of primary and middle students and develop the assessment scale in order to improve the scientificity, pertinence and effectiveness of character education. Based on theoretical standpoint of students' core competencies, an extensive analysis of related literature at home and abroad, the actual needs of our country, and a semi-open questionnaire survey of many frontline teachers, a two-dimension model of primary and middle school students' character in the Chinese cultural context is proposed, namely the two dimensions of pin and ge, each consisting of eight character traits. What's more, a scale of primary and middle school students' character is developed by means of the item analysis, the confirmatory factor analysis and the reliability and validity test. The results of application indicate that the students' character contains a structure of 16 first-order factors and 2 second-order factors and the related index of scale has reached the psychometric requirements. These findings not only provide effective evaluation tools for character of primary and middle schools but also establish a sound theoretical basis for implementing moral education and improving core competencies.