Summary: This paper proposes a Human-centered Pervasive Computing System Model (HPC), a Layered Architectural Analysis and Design Method (LAAD) and a Waterfall Prototyping Process Model (WPP). Based on the HPC model and the LAAD method, a pervasive computing based multimodal tele-home healthcare system is designed and partly implemented using the Waterfall Prototyping Process. The design and implementation issues are discussed in more detail. Some testing results are presented.