Abstract:Background. Often it is required to measure distinction or distance between two lines (for example, in evolutionary, structural or functional researches of biological lines). As line sequences of mitochondrial DNA approximately make 17 000 symbols {a, g, c, t}, in order to solve the set problem the authors chose objective algorithms of indistinct comparison that calculate the distance in polynomial time. In the research, when calculating the metrics of the known algorithms of inexact comparison of lines, there were received various results. The work purpose is to develop the methods of qualitative assessment of the received results. Development of qualitative assessment will allow to choose the most acceptable algorithm that will improve researches in various subject areas. Materials and methods. The theory of triangular norm in metric space was used as a method of research. Results. The initial data were obtained from the NCBI databank, and 30 line sequences of mitochondrial DNA were randomly chosen. As a result of perfomance of algorithms of comparison of 30 line sequences the authors adduced qualitative estimates. Conclusions. Using the obtained qualitative estimates of metrics the best algorithm of comparison of line sequences has been determined.