The combination of ultrasound and microreactor is an emerging and promising area.Due to its non-invasive nature and strong acoustic effects like radiation force and streaming,ultrasound has been used widely to manipulate samples, enhance mixing and prevent clogging in microreactors.On the other hand, with a well-defined micro-structure, microreactors provide an ideal environment to investigate and control the acoustic cavitation process, which is the main mechanism for most power ultrasound application.