Mixing phenomena by means of tracer technology are vitally important to understand the flow in metallurgical reactors, for example, continuous casting tundish. The widely used analysis methods are RTD (Residence Time Distribution) curve or F curve, which is a time dependent integral of RTD E curve. For the two methods, in the normalization process, the outflow percentage of a single-strand tundish or the summation of the outflow percentages of each strand in the multi-strand tundish are all limited to 100%. Thus, the total amount of tracer outflow information is concealed, which may lead to the problem of inaccurate results. This study proposes an analysis method of the outflow percentage, and proposes the calculation method to convert the physical experiment results into the real-time outflow percentage curve. In addition, based on the outflow percentage curve, the time-weighted average variance and the residual tracer percentage can be calculated and used to evaluate the uniformity of each strand and dead volume, respectively. In this study, the water model experimental data of a single-strand tundish and a four-strand delta shape tundish, which is installed by double weir or U-shaped weir, under normal condition and one strand blockage conditions are all analyzed by the proposed outflow percentage method. The results show that the experimental results can be proofread by using the outflow percentage method to further verify the repeatability of the water model experiments. Meanwhile, the difference in the percentage of outflow at the end of the monitoring time and the proportion of the dead zone at twice of the theoretical residence time can be compared in double weir four-strand tundish and U-shaped weir four-strand tundish. It can also intuitively compare the uniformity of each strand of different multi-strand tundishes, and the distribution and uniformity of the tracer in other outlets after one of the strands is blocked.