The invention belongs to the fields of chemistry and chemical Industry as well as environmental protection, and relates to a method for efficiently improving activity of a catalyst of Silicalite-1(silicon HZSM-5 zeolite) loaded with Ru for catalyzing N2O to decompose into O2 and N2, wherein carriers are prepared by a hydro-thermal synthesis method; an ultrasonic immersing method is adopted to load the active element Ru on the surfaces of the carriers in an oxidate mode, and the N2O is decomposed under the condition that the soaking time is shortened by half compared with the common immersing method, the catalytic reaction temperature is 200-550 DEG C, the pressure is 0.1-0.5MPa, the concentration of N2O is 1,000-5,000ppm, helium is balance gas, gas hourly space velocity of the mixed gas ranges from 5,000 to 50,000h<-1>; and the crystallization time of the carriers is 5-7 days, which has obvious influence on the catalytic reaction activity. The invention has simple preparation technology, and the prepared catalyst has efficient catalytic activity and stability; and the resolution ratio of the N2O is 100% at the temperature of 400DEG C, and the catalyst has efficient N2O decomposition activity.