Based on the decay scheme

the formulas for calculating the correction factors of theγ-ray coincidence summing effects are deduced. The corrections for the coincidence of γ- rays with X-rays （from electron capture or internal conversition） and with annihilation quanta from positron decay are also discussed. The fullenergy -peak efficiency of the HPGe detector at defferent source - to - detector distance is calibrated by using the multi -γ- ray sources calibration method combined with the distance variation method with several single - γ- ray sources. The error of the efficiency is less than 3% at the energy range of 60 - 1116 keV. The peak -to -total ratio is determined for the single -γ-ray sources. The coincidence summing correction factors for Eu

Co and Na are calculated.