This paper presents an active measurement model (AMM) for software process control and improvement, and the related measurement method. AMM formally describes the goal, feature, and indicator of software process, and their relationship. AMM also provides some principles, methods, and techniques to determine the measurement of software process. Based on AMM, on one hand, software organizations can deduce the appropriate measurement process according to the goals of the processes they focus; on the other hand, they can also identify the opportunity and roadmap of improvement according to the result of measurement. It will provide an effective support for software organization to make an accurate decision and achieve a successful result.