This paper aims at developing a procedural framework for the development and validation of diagnostic speaking tests. The researcher reviews the current available models of speaking performance, analyzes the distinctive features and then points out the implications for the development of a procedural framework for diagnostic speaking tests. On basis of the overview and the experience gained from the development of Diagnostic College English Speaking Test, The researcher elaborates on the process of the development of the procedural framework. The framework is composed of four major phases: phase 1 needs analysis, phase 2 test design, phase 3 test piloting, administration and validation, and phase 4 test impact. Each phase is further divided into several steps, each having concrete aims and objectives. Literatures relevant to each component of the procedural framework are also recommended by the researcher to help teachers to develop their own diagnostic tests. The paper concludes with suggestions for further research on the development of computerized diagnostic assessment systems.