The history and recent development of sintering stress of powder metallurgical materials are introduced systemically. The methods of the sintering stress calculation, including the energy difference method, the curvature method and the force balance method are stated. The present attention on the sintering stress is the ideal two-sphere model and the repeating unit cell model. But all these calculation methods or models can not reflect the sintering stress of porous materials in the factual sintering condition. So, it is essential to construct a sintering model and to develop a method to calculate the un-identical sphere model to describe the factual sintering stress. Computer simulation of sintering stress is the direction of further investigation on the un-identical sphere model.