The measurement quality of the early childhood program is of great importance for the children’s development. 155 classrooms sampled from the eastern part of China, were observed and assessed by 28 raters. The scale in the study which is called Chinese Early Childhood Environment Rating Scale(CECERS) is made up of 46 items, 8 subscales, they are Space and Furnishing, Person Care Routines, Curriculum Planning and Implementation, Whole-Group Instruction, Activities, Language-Reasoning, Guidance and Interactions, Parents and Staff. Usually, one classroom was observed and assessed by 2 or 3 raters alone at the same time. In this measurement situation, rater severity, inter-rater reliability, the bias between the rater and the class, and bias between the rater and the item were analyzed from three facets, they are the class, the rater and the item respectively. Facets software (MFRM3.68.1) were adopted in this study. The results of the analysis show that: there were significantly different among the 28 raters; the consistency from the 3 raters was high, at the same time, the internal consistency was stable from the rest of 25 raters; a further analysis of the unexpected responses from the three raters showed that, there was no common attribute of the classes and the same of the items；the interaction between the rater and classroom was not different significantly, the ratio of the significant bias is 8.02%, the further analysis based of the significant bias showed that, there were no common attribute among these classes；the interaction between the rater and the item was significantly different, the items with significant bias was computed, it found that there was a large deviation in the item 45 and item 13;the deviation was less in the items such as item 22, 25 and so on, which were more familiar for the raters. All of these provided the psychometric basis for the training, the standards and the constructing of the rater bank from the perspective of IRT.