This study aims to carry out supercritical water oxidation (SCWO) of unsymmetrical dimethy-hydrazine in a tubular continuous flow reactor system with an H_2O_2 oxidant, at a temperature range between 480 ℃ and 550 ℃ at the pressure of 30 MPa. The study also described the general principle for the COD removal by using a power-law. The results show that the oxidative decomposition of unsymmetrical dimethy-hydrazine can be done quickly with a high COD removal speed up to 93.5% within 5.8 s at 550 ℃ and 30 MPa ...