Abstract The human small intestine is responsible for virtually all nutrient uptake and more than 95% of the water absorption in digestion, which is attributed to the vast mucosal surface area and the peristalsis of small intestine. Under the broad conceptual framework of bio-inspired chemical process engineering, by mimicking the structure and functions of small intestine, a flexible tubular reactor with villous protrusions distributed evenly on the inner wall was designed and constructed in this study. In order to understand the flow behavior in the reactor, the residence time distribution (RTD) of fluid particles in the reactor was measured by introducing electrochemical active tracer. Also, a simple mechanism of peristalsis was introduced, and its effects on the RTD in the reactor were investigated. The experimental results showed that the tailing of RTD function curve in the small intestine model reactor was extended significantly compared to a normal tubular reactors. The residence time and mixing of fluid (particles) in the reactor can be regulated efficiently by controlling the peristaltic actions (frequency and location).