|（Law School，South China Normal University，Guangzhou 510006，China)
Abstract: Cause of justification is a balance used to maintain the fairness of sports competition activities; the spirit of modesty should be adhered to when criminal law involves in a dangerous situation or harmful consequence pro-duced by a sports competition activity. Based on the existing crime constitution theory system, according to the vic-tim’s commitment theory, the justification of a sports competition injury behavior should be strictly identified in terms of commitment theme, commitment time, commitment subject, commitment authenticity, commitment ex-pression and acknowledge etc if it has not been clearly specified by legislation. In terms of criminal lawsuit testi-mony of a victim’s commitment, according to the stipulation of the new criminal procedure law, the prosecutor un-dertakes the guilty proving responsibility all the time, the standard of proof should be the standard of conviction, while the defender is the standard of probability.
Key words: sports law；cause of justification；proving responsibility；victim’s commitment；competitive sports