A numerical model was proposed to predict the co-injection step of the powder co-injection moulding (PCM) process. Several assumptions were established for the purpose of simplifying the physical models. The melt front was traced by a modified control volume method, in which the maximum thickness of core feedstock was taken into consideration. Such modification can overcome the shortage of Hele-Shaw equitation in predicting 3D flow behaviour. By using this model, the movement of the skin melt front and core/skin interface, and the profile of temperature and pressure fields were obtained. The simulations were in good accordance with the experimental results. The thickness and the penetration distance of the core feedstock were accurately predicted. The deviation between the simulated and experimental results was due to the uneven shrinkage of the green part during cooling. (C) 2016 Elsevier B.V. All rights reserved.