The Madelung constants of atomic chain is calculated by accumulation method，Evjen method and mean value method，and the results are compared. It is found that the Madelung constants of atomic chain with finite length is different from that of circles. It is also found that the Evjen method is equivalent to the mean value method by means of plotting graph. Two errors in the paper “Analytical solutions of madelung constant of double atomic chain on circles”are revised，and it is proposed to revise the definition of dimerization Madelung constant，so that its physical concept is more obvious.