Photo-thermal imaging (PTI) is an imaging technique that can provide a resolution exceeding the diffraction limit. The theoretical resolution limit is less than 1 nm, therefore it is particularly suited to analyse particles in nano-size targets. It is also a non-labelling, high temporal resolution technique that can be conducted in a normal live cell environment. In this paper, a PT imaging microscopy system has been demonstrated and the integrity of the system is verified through a series of experiments on different samples, including red polystyrene bead and carbon nano-tube. The PTI technique can find further applications in biology studies for the visualization of cell organelles and apoptosis studies.