The board of directors,as the important component of the internal governance mechanism,has important in- fluence on firm achievements,but the forefathers' researches were mostly carried out from one aspect,and they has not considered the function of the market structure and the difference of ownership structure on the relationship.This paper regards listed company under the competitive market structure as the research object,studies the relationship between the characters of board of directors and firm achievements from the scale,structure,meeting frequencies and encourages respects,and the difference of characters of board of directors,the difference of firm achievements,the difference of the relationship under different ownership structure.According to the conclusion,the paper makes some suggestions.