Structural equation model (SEM),which is a method of building,estamating and testing causality modeling,has been being used widely in the fields of psychology,sociology,behavior science and medicine. Goodness index is usually used for evaluating the goodness effect of models,but there are more than 40 indexs for SEM,and the results of different ones are not same. So which indexes are credible becomes a concerned topic for users. On the base of collecting many literatures,we summarized systematically the category and characters of indexes of SEM. By the method of comparing analysis,we find NNFI and RMSEA are credible,the second is CFI,RNI and Mc. When estamating parameters with ML or GLS,we find SRMR has better effect.