Through the analysis of many creep rate-time or creep rate-strain curves of -single phase Ni-20mass% Cr alloy single crystals with various stress axes, it was clarified that the creep deformation manners at lower stresses are drastically different to those at higher stresses. These creep features at lower stresses are summarized into three ones as follows. (i) The fully extended transient stage occupies the considerable ratio of rupture life. (ii) The steady state stage disappears, because the transient stage directly connected with the accelerating stage. (iii) The origin of the onset of accelerating stage is regarded as the formation of the dynamic recrystallized grain. These difference in creep deformation manner were caused by the predominant operation of the primary slip system and then the homogeneous evolution of dislocation substructures.