In the paper we study the Yang-Mills effective action in the four-dimensional space-time by using background field formalism. We give an explicit way of cutoff regularization procedure, then do a two-loop renormalization and calculate a second $\beta$-function coefficient. We also show that the two-loop singularity contains only logarithmic part in the first degree. At the same time additional properties of a Green function regular part are obtained. Comment: LaTeX, 25 pages, 1 figure
