Software dependability modelling involves simultaneous consideration of several incompatible and often conflicting objectives, while hypervolume-based multi-objective evolutionary algorithm (MOEA) has been shown to produce better results for multi-objective problem in practice. A frame of reliability model optimization with hypervolume based MOEA is presented. Focusing on the key issue of hypervolume based MOEA, a new algorithm, set hypervolume contribution by slicing objective (SHSO), is proposed for calculating the exclusive hypervolume contribution of a subset to the whole nondominated set directly for small dimension. For the special case of SHSO, CHSO (the contribution of a point to hypervolume by slicing objective) is improved with heuristics. The feasibility and efficiency of developed algorithms are shown by experiments. © 2011 TSI® Press.