The capability of measuring 3-dimensional wind and tropopause structure with relatively high time and vertical resolution makes VHF radar a potentially significant tool for studying various processes of the atmosphere. Here the potential detection of possible stratospheric intrusion events is discussed using the Beijing MST radar located at Xianghe (39.75° N, 116.96° E). During the passage of a cut-off low in late November 2014, a deep V-shaped tropopause structure, and strong downdrafts (> 0.8 m/s) immediately preceding the rapid tropopause ascent (> 0.2 km/h) were observed. Within the height region of the downdrafts, the normal radar-tropopause layer seems to be destroyed (weakened) with the decreased echo intensity. Analysis results from global reanalysis and the satellite data, as well as the trajectory model have shown the clear evidence of the downward stratospheric intrusions (dry ozone-rich and depleted methane air) associated with the strong downdrafts. According to the previous studies and the present case observation, the strong downdrafts preceding rapid tropopause ascent are considered as a significant signature of stratospheric intrusions. Twenty typical cases of such strong downdrafts, occurring during various synoptic processes in different seasons, have been presented and 16 of them are exactly associated with some form of stratospheric intrusions. Four years (2012–2015) of such downdrafts are further discussed. The observations reveal that the strong downdrafts preceding the rapid tropopause ascent can be a valuable diagnostic for monitoring intrusion events, which will gain a better understanding of stratospheric intrusions in VHF radar observations.