Purposes: Posner divided the attentional process into three compositions: alerting; orienting; exective control. Then Costa founded “bilingual effect” in all the compositions except orienting. We founded that there is an inhibition composition in orienting that they neglected. It is “Inhibition of rentrn, abbreviated IOR.So this research we want to use the paradigm of IOR to discuss if the bilingual effect occurred on the composition of orienting, and if this effect occurred depended on the skilled difference of language two. Procedures and Method: We designed the experiment by 3×2×2.The first variable is the type of subjects refers to 15 balance bilingual children, 16 unbalance bilingual children and 17singual children. The second variable is SOA refers to 400ms and 650ms.The third variable is location refers to cue and target at the same location or different location. The experiment concluded four conditions, every condition have 20 trials. All the 80 trials appeared random and no three trails were the same. All the subjects have a practice before the formal experiment. They can not begin if the practice error rate was higher than 5%.In the experiment, the fixation was presented 200ms; and then the peripheral cue was presented 200ms; and then central cue was presented 100ms; and then the cue presented 100ms or 350ms in order to control the SOA; after all the target was presented at the peripheral location random. The work of subjects is press the key of space when the target was appeared. Response time and error rate was recorded by the software of DMDX. Results: One unbalance bilingual children and one singual child were rejected because of their practice rate was still higher than 5%. Then repose time was analyzed by repeated measures of ANOVA. The results showed: the main effect was significant, F (1, 42) =37.03, P<0.05.The interaction effect of SOA and location was significant F (1, 42) =109.81, P<0.05. There was no main effect and interaction effect on error rate. More analyses was founded that IOR appeared when SOA was 600ms, but not appeared on 400ms.The difference effect of IOR was significant between balance bilingual children and signal children. There is no significant difference between other types of children. Conclusions: (1) Bilingual study promotes the development of inhibition control, especially in the orienting compositions. (2)Whether bilingual study promotes inhibition control depend on the compence of language two.