How to enable the robots cooperative efficiently is one of the most important problems in multi-robot domain. Improving the cooperation diversity can give the system chance to fit more kinds of situation. In this paper, a concept 'personality1 is introduced into the multi-robot system and help to improve the diversity of the system. The previously homogenous robots may possess different personalities and become heterogeneous ones. With personality changing, the value inclination of a robot is changing either, and the behave style of a robot appears to be different with before. And when the multi-robot system works in an unknown environment, their personalities may evolve through the labor division and cooperation process to try to enlarge the benefit. We bring different personality into the multiple targets observation problem and try to analyze the influence of personality in this problem.