Abstract: The calculation for unit pressure at the coiler's drum as a plane problem in elasticity is analyzed, and developed a formula, in which is taken account of different modulas inradial and tangential direction of the strip coils. This formula is more simple and exact than that of Chiang Chao. In this paper the theoretical determining method about radial compression coefficient of the strip coils is studied. The results obtained theoretically and experimentally are contrasted and discussed.