Abstract: Project delay is still a common phenomenon in software development,which may affect seriously in software quality and cost, even result in project failure. Risk control is thus essential for project schedule management. The paper analyzed the quantitative approaches for schedule risk analysis and management. It surveyed and compared the three typical models of software project management, including PERT/CPM,Critical Chain/Buffer Management, Event Chain Methodology. Among them, the Event Chain is a newly proposed model and risk analysis method from 2004. It introduces the event model into traditional models of activitics,which captures the basic characteristics of risk occurrence and propagation. It represents a new viewpoint with a separated and dedicated risk model, and promotes a innovative approach for quantitative risk analysis.

Key words: Software project,Schedule risk,Quantitative analysis,Event chain