根据现有的有关Fisher信息量的结论，通过逆危险率函数，推出了Fisher信息量的一种表达式，给出了一个被截尾的随机变量所保留的Fisher信息量和丢失的Fisher信息量的表达式，通过这种表达式可看到删失数据下Fisher信息量的组成成分。最后，得到了删失数据下Fisher信息量的一个性质。Through using the reversed hazard rate of random variables, this paper derives an expression of Fisher information based on the knowledge of Fisher information in hand. The expression of the retained and lost Fisher information of a random variable due to censorship is produced. So the component of Fisher information under censorship is detected. Then, this paper gives a property of Fisher information in censored data.