This study examined an inhibitory function in the processes of consecutive interpreting between Chinese and Japanese. In the experiment, the difficulty of the source language (SL) was manipulated for an advanced class of Chinese students learning Japanese as second language. The results revealed the following. (1) Inhibitory function affects interpreting performance overall, but its effect is more stable in the consecutive interpreting from Japanese to Chinese than that from Chinese to Japanese. (2) In the case of higher SL difficulty, the effect of inhibitory function pronounced in both directions of consecutive interpreting. (3) In the case of lower SL difficulty, the effect of inhibitory function is more pronounced in the consecutive interpreting from Japanese to Chinese than that from Chinese to Japanese. These results indicated that the inhibitory function in the interpreting processes is constrained by the difficulty of SL and may depend on the direction of the consecutive interpreting, namely whether from native language to second language or vice versa.