In order to adjust functions of mobile virtual instruments dynamically,a mobile virtual instrument browser based on iOS platform has been proposed. The principle is to turn the browser into different virtual instruments by loading different virtual instrument scripts into it.A virtual instrument consists of several controls with many input and output interfaces.The assembly and communication of controls are based on KVO,and scripts are used to describe the assembly. All control classes inherit from UIView class and need to call and override a part of UIView functions. The feasibility of the virtual instrument browser has been demonstrated by a signal generating-and-displaying instrument.