Abstract：Legal principles reflect the values and spirits of law.How to apply principles depends on the concrete situation of rules in a particular case.When there is a rule in a particular case,the principle helps to keep a rule from being misused.If there isn't a rule,the judge can use a principle to supplement the gap in law.When a principle conflicts with a rule or another principle,the judge needs to balance the weight of every principle and chooses more important principle.The balancing should abide by the proportion rule.Moreover,the judge must justify the balancing.Only the balancing accords to the proportion rule,can it be rational.
