In China and other developing countries, the electricity retail pricing structure is still based on customer classification, and capacity cost allocation is a long-term and important issue. To allocate capacity cost for various customers is relation to their time-varying load characteristics. For this, the paper in-depth analyses the relationship between the power system generation capacity responsibility and the time-varying characteristics of power load demand, applying the economic ideas and methods of the peak-load problem; presents a capacity cost responsibility model, by which the power generation capacity cost is allocated for system load in all time; and then established the classified customer cost-sharing model of power generation capacity with peak-load pricing theory, which takes into account the users load characteristics and overcomes the shortcoming of the existing methods that generation capacity responsibility is only dependence on the power load value at a given moment. Cases verify the rationality and fairness of the cost-sharing model.