To solve the problems of poor flow field distribution and uneven quality of each stream caused by the unreasonable structure of the orifice of the ten-stream tundish turbulence inhibitor in a steel plant, an experimental 1:3 hydraulic model was established to conduct water model tests by using the similarity principle. On the basis of different orifice structures, the uniformity of each stream was considered fully and then the optimal structure of the orifice and the effect of the orifice structures on the tundish flow field were obtained by means of the comprehensive analysis of the residence time distribution curves of liquid in the tundish and the display characteristics of the flow field. Experimental results showed that for the long-distance and multi-stream tundish of no weir structure, the size, quantity, and direction of the inner diameter of the orifice of the turbulence inhibitor all affected the flow field of the tundish, and the effect of the inner diameter of the orifice was the most significant. The inner diameter of the optimal orifice designed in this work reduced from 53 mm to 30 mm in the prototype, the dead zone ratio reduced from 54.05% to 34.69%, the maximum standard deviation of the F curve reduced from 0.0154 to 0.0035, the flow field of the tundish was improved, and the flow field of each flow was improved. The uniformity among the streams was significantly improved. The number of orifices increased from 1 to 3, the proportion of dead zone increased from 34.69% to 46.05%, and the maximum standard deviation of the F curve increased from 0.0035 to 0.0062. The more the number of orifices was, the higher the proportion of dead zone in the flow field was. The larger the value was, the worse the consistency of the flow field of each nozzle was. For the long-distance and multi-stream tundish, it was recommended to improve the flow field of the tundish by appropriately changing the inner diameter of the orifice, reducing the number of orifices.