The microwave-based liquid sensors are indispensable techniques which can provide many advantages such as low cost, real time and label free for biological or chemical measurements. Metamaterials are well suitable for sensing applications due to the narrow spectral feature. A flexible plasmonic microfluidic sensor has been proposed to obtain a non-invasive measurement of different liquid solutions. The resonance frequency changes from 5.133 GHz to 5.006 GHz, with a frequency shift of 127 MHz, when the microfluidic channel is filled with deionized (DI) water.