By the method of the oscillating sphere, as developed by Andrade and Chiong, we have determined the viscosities of three samples (K: 49%, 51%, 74%) of the liquid alloy NaK, the temperature range being about 300℃. The result showed that the liquid alloys in the temperature range measured follow the Andrade's law η =Beb/T quite satisfactorily. In the paper, in addition to descriptions of apparatus design and new improvements made, some salient points of interest are discussed.