The glass tube rotameter is usually used only for site instructions, without remote transmission. In this paper, the inductance sensor detects the float's displacement, with the coil around the inner tube, core installed on the float. As a result, the displacement of the float caused by the flow can reflect the inductor changes. It turns the inductance changes to voltage amplitude changes through the three-point capacitance oscillator circuit, and we can get the DC voltage signal by filtering the sine wave through high-frequency filter circuit. After sampling process in AD converter, the output voltage can be measured. Based on the relationship between voltage and inductance, and inductance and flow, we can program in the MSP430 to get flow. The realization of non-electrify electrometric measurement by transforming float displacement changes to inductance changes improves the measurement accuracy, and achieves the remote transmission by precision current transmitter.