Sintering diagram for 316L stainless steel fibers has been constructed based on a two joint-fibers geometric model and material constants. The results show that grain-boundary diffusion is the dominant neck-growth mechanism at relatively low sintering temperature for a long dwelling time, while surface diffusion is the dominant neck-growth mechanism at relatively high sintering temperature for a short dwelling time. Volume diffusion cannot be the dominant mechanism during the entire sintering process due to the high activation energy of volume diffusion compared with that of surface or grain-boundary diffusion. Moreover, joint-fiber has no substantial impact on the sintering mechanism. The constructed sintering diagram is verified through the experimental results. The results show that excellent agreement is found between the predicted and measured results at higher sintering temperature of 1300 degrees C. However, un-ignored discrepancy is found out between the measured and calculated relative neck size of joint-fibers sintered at 1100 degrees C, which reach a value of 30%-40%. The appreciable discrepancy at 1100 degrees C is attributed to the fact that the sintering is performed at a temperature near the boundary line dividing grain-boundary-diffusion controlling field and surface-diffusion controlling field, which lead to a significant contribution of neck growth from grain-boundary diffusion. The constructed sintering diagram for 316L stainless steel fiber can be used as a guide to design and interpret experiments, and has potential applications in solving practical sintering problems. (C) 2015 Elsevier B.V. All rights reserved.