The plume photograph from laser ablation of metal Cu in different Ar pressure was taken,and it has different colour in different region. The effect of pressure over 265 kPa-98.2 kPa on plume colour was studied. Spatial-resolved spectral measurment technique was used to study the spatial emission intensity distributions of plume by pulsed laser ablation of metal Cu in different pressure. The excimer dynamics of laser ablation of Cu surface was studied,the microscopic excimer mechanism of laser laser ablation of Cu surface was discussed. The results show that the plume may be explained using a simple model based on plume is made of three region,the region ablation mechanism is different from one another,the excited Cu atoms and Cu ions may be produced from different mechanism. The model can be used to explain the experimental results qualitatively.