There is a need to clarify the phase transition nucleation and propagation phenomena in a polycrystalline NiTi shape memory alloy under extremely small-scale compressive loading. In the present study, the strain-stress indentation curves, temperature rise, phase transition volume, plastic volume and hardness of this smart material during static and dynamic loading are discussed and a hypothesis is proposed for the nucleation and propagation of phase transition volume underneath the stressed spot. According to the indentation curve, jagged loading/unloading stages are the evidences of discrete nucleation and propagation in the phase transformed zone. (C) 2016 Elsevier Ltd. All rights reserved.