The method of numerical experiment on NN (1 < N < 1000) square lattices simulating a biphase granular superconducting film determines the threshold concentration of superconducting grains: C1, at which separate closed intergranular current of a contour blocking nonsuperconducting areas appears, C2, at which an incorporated superconducting contour with its borders entering a lateral surface of a sample appears and С0R at which closed current runs through a granular film in the form of a cylinder’s lateral surface. At N = 1000 these concentration equals C1 = 0,1735  0,0235, C2 = 0,7150  0,0100 and С0R = 0,5939  0,0027. The dependence of the number of normal and superconducting contours blocked by closed intergranular superconducting currents on the concentration of superconducting grains is determined in the article.