During beam blank continuous casting production, lots of longitudinal cracks easily appear on the surface. In order to study the initiation locations of longitudinal surface cracks in the mold, a coupled thermo–elasto–plastic finite element model was established on the software ABAQUS. According to the results, it can be inferred that the forming locations of longitudinal surface cracks easily appear on the surface of the fillet, the web center, the flange tip and the flange center. Moreover, initiation locations forming longitudinal surface cracks should be: on fillet at a distance of 200mm to the meniscus, and the other three sections at a distance of 180mm to the meniscus. This study can not only provide stress boundary conditions for the research of longitudinal surface cracks’ initiation and growth, but also help the actual production to decrease longitudinal cracks on the beam blank.