Prioritizing requirements priority is the action that stakeholders assign the orders of requirements to be implemented. It is the basement of the iteration plan. Existent methods of prioritizing requirements are inadequate to support stakeholders’ negotiation or the adjustment of requirements’ priorities. These shortages always lead to a rigid iteration plan that is difficult to be adjusted to adapt changes of requirements and environments. In this paper, a risk-driven adaptive method is put forward for prioritizing requirements which combines adaptive planning and risk-driven methodologies. Requirements are prioritized adaptively, and risks are used as the foundation of priorities decisions. The negotiability and adjustability of requirements priorities can be enhanced by the method. The negotiable and adjustable requirements priorities improve the developers’ capability of controlling requirements and reduce the faults of software project caused by requirements.