It is an important part that support interfere correction in the wind tunnel test correction system,the support interfere of wind tunnel airflow is inevitable,even the measure of some parameters could far warp to real,so the method to correct support interfere is the key of wind tunnel data correction. The ventral support is normal used in low speed wind tunnel test,two-steps imaging method works at correction. We analyse the support correction of a low speed wind tunnel test about the certain transport airplane,numerical simulate the influence of the support to wind tunnel airflow,research the current wind tunnel support correct system.