The degradation behavior of 2,4-dinitrophenol (DNP) by low-temperature plasma was investigated and the effect of some factors that might affect the degradation process was further examined. The results indicated that DNP could be effectively removed from aqueous solution. The degradation value was 83.6% when the input power was 150 W and 60 s was selected as the discharge time. Increasing the input power increased the degradation efficiency. The degradation process fitted first-order dynamics and the reduction was mainly caused by the reaction of DNP with OH. The degradation efficiency decreased with the increase of initial concentration at the same discharge time. H2O2 at the concentration of 0.25% enhanced the degradation process, however, hindered the degradation at 1.00 and 2.00%. The presence of Fe2+ could benefit DNP degradation. However, the increment in degradation efficiency might be suppressed to some extent at a high concentration level. Cu2+ inhibited the degradation process within 30 s and enhanced the reduction after 30 s. Furthermore, the increment of Cu2+ concentration could enhance the effect. A little acid environment was conducive to DNP degradation and the pH value became lower with increasing discharge time by low-temperature plasma.