In order to measure small permittivity changes of chemical solutions caused by temperature and concentration，a cancel type sensor is proposed. The device consists of an in-phase Wilkinson power divider and an out-of- phase power divider，and the two dividers are connected by 2 slot lines. Therefore，two branches called reference and test branch are formed respectively，on which the Material Under Test(MUT) and reference(REF) material are placed. The permittivity difference between the MUT and REF is reflected by measuring the cancellation of the two signals. Simulation results show that the sensor proposed can improve amplitude sensitivity of transmission parameters by more than 18 dB，compared with traditional Coplanar Waveguide(CPW) measurement.