Ice clouds measurement technology plays an important role in improving the accuracy of the weather forecast and monitoring extreme weather phenomena and so on. Considering the physical dimension and shape distribution of ice-cloud particles, the problem of ice-clouds detecting could be solved by using terahertz passive remote sensing instrument. As an important detecting channel, the 664GHz RF front-end of receiver mainly includes a 664GHz sub-harmonic mixer, a 332GHz doubler and a 166GHz high power source. Based on the design of terahertz doubler, a 166GHz high power frequency multiplying source has been realized by using two way power-combined technology. The measured results show that the output power of above-mentioned source is more than 46mW in 164~172GHz and the highest output power is 59mW at 168GHz. The above-mentioned research could solve the problem of lacking of the G band high power source in the LO chain, and provide technical support for the design of terahertz system working at higher frequency.