Juries represent the ordinary public and therefore are more likely to judge in line with generally accepted values of the society. Justice and equity are the standards of an eligible jury, and the jury selection is meant to ensure “counterbalancing of biases” or canceling out individual biases (Hastie, Penrod & Pennington, 1983). However, jury trials are often vulnerable to the effects of prejudice and stereotypes of the jury, by geographical or historical factors, and it tend to be harmful to certain groups. For example, juror characteristics, such as gender, religion, education level, socio-economic status (Hastie et al., 1983; Wrighstman, Kassim & Willis, 1987), and racial prejudices (Urszbat, 2005). And attorneys’ intonation, posture, attractiveness, confidence, and credibility also affect juries’ perception and their judgments (Jakubaszek, 2014). Most significant, the characteristics of defendants like gender and age would affect jury decision making (Pazzulo, Dempsey, Meader & Allen, 2010). These prejudices and stereotypes cause in-group-out-group bias during the trial process. In-group bias means in-group favoritism that refers to the fact that under certain conditions people will preference and have an affinity for one’s in-group over the out-group, or anyone viewed as outside the in-group. It is usually expressed in one 's evaluation of others, linking, allocation of resources and many other ways (Aronson, E., Wilson, T. D. & Akert, R. D., 2009). And out-group bias is the phenomenon in which an out-group is perceived as being threatening to the members of an in-group ( Hewstone, M.; Rubin, M.; Willis, H., 2002) defined as out-group derogation. It is a matter of favoritism towards an in-group and the absence of equivalent favoritism towards an out-group (Brewers, Marilynn B., 1999). Outgroup derogation often…