Objective To raise a quantitative indicator for the waveform similarity between different signals of the same kind and apply it to the analysis on the vertical force signals from the rolling manipulation. Method After two signals of the same kind were normalized and their waveform errors were analyzed, the waveform similarity, which was to be utilized to describe the extent to which two signals were similar to each other, was defined. Then, the vertical force signals of the rolling manipulation operated by several experts, graduates who have learned the manipulation for some time and beginners were measured, respectively. Subsequently, the values of the waveform similarity between the three different groups of signals were calculated. Results The similarity between the experts’ signals was relatively high, so it was reasonable to be used as a template for other operators’ signals to be compared with. Further calculation revealed that the waveform similarity between the experts’ signals and the graduates’ was generally lower than that between the experts’, and the similarity between the experts’ and the beginners’ was the lowest. There was significant difference between the three groups. Conclusions The waveform similarity raised in this paper could serve as a quantitative indicator for the similarity between different vertical force signals from the rolling manipulation, and this method was also applicable to the similarity evaluation between other approximate periodic signals.