Context : Analysis of new radial velocity measurements of the active giant PZ Mon is presented .

Aims : Only in 2015 was reported that PZ Mon may be classified as RS CVn giant .
At the same time was discovered the variability of radial velocity .
However , lack of the data is not allowed to determine parameters of the system .

Methods : The measurements of radial velocity were performed using Radial Velocity Meter installed at the Simeiz 1-m telescope of the Crimean Astrophysical Observatory and using echelle spectrographs installed at the 2-m Zeiss telescope of the Terskol Observatory and the 6-m telescope BTA of the Special Astrophysical Observatory of the Russian Academy of Sciences .

Results : We estimated parameters of this binary system including the \gamma -velocity 25.5 \pm 0.3 km s ^ { -1 } , the period on the circular orbit P = 34.15 \pm 0.02 days , the mass of the secondary component M _ { 2 } =0.14 M _ { \odot } , and the mass ratio q = 0.09

Conclusions : The mass ratio is a smallest value among known RS CVn type giants .
Combined with photometric data we conclude that PZ Mon is a system with synchronous rotation , and there is a big cool spotted area on the stellar surface towards to the secondary component that provides the optical variability .