On the issues of solving several problems such as low accuracy, water waste and low efficiency in traditional Standard Tank verification methods. This paper provides a set of standard tank automatic verification method based on the principle of visual technology. The standard facility of capacity verification is developed by this method. Moreover, we developed the mechanical structure automatically docking with metal tank and designed a verification system, whose software and hardware is based on LabVIEW platform and PLC. In addition, it conducts the uncertainty evaluation on the devices as well. According to results of this principle, the standard facility of this structure can maintain stability of capacity and state parameters during verification. Experimental results indicate the verification efficiency is improved by more than 30%, the uncertainty of verification is 6.4mL(k=2), which can meet the requirements of detection for metal tank.