Abstract: In today′s Integrated Circuits design and fabrication process,the users′chips are likely to be implanted Hardware Trojans,which brings unpredictable hazards.The Hardware Trojan has become a research focus in recently years.Firstly,the concept of Hardware Trojan and the feature of low activation probability are given.And then insert Trojan in the multiplier circuit,analysis the influence of activation probability to original trigger circuit in power and consumption.Lastly,verified the validity of Trojan.