Many tunnels are going to be driven in China. In order to reduce accidents, the effective measure is to carry out risk evaluation in advance. So it is necessary to study risk acceptance criteria for providing standard of risk evaluation. Individual risk and social risk acceptance criteria are mainly studied in this paper. Individual risk can be derived by the product of former average individual risk level and influence coefficient of national laws. The shape of FN-curve is determined by the combination of neutral and conservative utility theory. Parameters in the curve equations can be calculated by investigating former risk data and known conditions.