The measurement performance of ultrasonic flow meters (UFMs) is highly sensitive to the installation location. In practical applications, non-standard testing conditions are inevitable. Currently, there is a lack of research on the error characteristics and correction models for valve-induced flow disturbances. Taking butterfly valves as the research subject, finite element numerical models for UFM measurements under various conditions including different inlet velocities, pipe diameters, valve positions, and valve openings were constructed. The impact of butterfly valves on flow field characteristics and error characteristics was investigated, and ultimately error correction models for UFMs were established. The results show that the fluid inside the pipeline experiences a reduction in cross-sectional area due to the obstruction caused by the valve, resulting in high-velocity regions between the valve and pipe wall. The velocity distribution on the cross-sections of the pipeline upstream and downstream of the valve becomes distorted, with the degree of distortion gradually decreasing as the distance from the valve increases. When the distance between the flow meter and the downstream valve exceeds 0.6D (D is the diameter of the pipeline), the pipe diameters can be divided into two groups based on the error characteristics, 0.1 ~ 0.3 m and 0.4 ~ 0.6 m respectively. Two error correction models can be established for the two groups. When the distance between the flow meter and the upstream valve exceeds 5D, the measurement errors for pipe diameters in the range of 0.1 ~ 0.6 m show strong consistency, allowing for the establishment of a unified error correction model. After applying the correction model, the flow measurement error is reduced to below 2.0%. For valve openings in the range of 30° to 75°, when the distances between the flow meter and the downstream and upstream valves exceed 0.6D and 5D, respectively, the measurement errors exhibit strong consistency. Under fixed valve positions, a unified correction model can be established for different valve openings. After applying the correction model, the flow measurement error is reduced to below 2.0%. The research results provide a theoretical basis and model support for expanding the application range of UFMs under non-standard testing conditions.