In the “solid-gas-liquid” system, the effects of soil moisture on the extractability of p-NCB in two soils and soil components (e.g. Gaolinite, Humic acids and their complex) were studied to explore the inner mechanisms. The effect of soil moisture on the extractability of p-NCB was conducted by spiking and subsequent moisture control of the soil samples. The results showed that soil moisture decreased the extractability of p-NCB on soils considerably. In the soil constituents-simulation experiments, the effect of sample moisture on the extractability of p-NCB in gaolinite was the maximum. Humic acids eliminated the effect of sample moisture on the extractability. The extractability decreased little after 21 days reaction suggested that aging of p-NCB on soils could be divided into two stage: from the beginning to less than 21 days was the fast aging stage, and after that was the stabilization stage. The extractability of p-NCB on the dry samples was almost unchanged after 120 days experiment, suggesting aging of p-NCB was not obvious on the dry soil samples.