Two-drum winch is one of the log pulling equipment effectivelly in steep ten-ain. The paper gives a brief of the process determining some working parameters affecting to productivity and unit power consumption when extracting logs by two-drum winch. From operational principle when winching by the two-drum winch, the equations determining productivity and unit power consumption have been established. Based on analysis of the groups of the affecting parameters, two practical significant working parameters are selected to study. That are pulling speed (V) and load (Q). Applying experimental planning method with support from computer and modem measuring equipment, the experimental equations relating between studied and affected parameters have been established. Solving these equations determined optimum pulling speed V = 0.325 mls and optimum load Q = 0.657 T when productivity is maximum, Ngmax = 1.805 m3/h and unit power consumption is minimum, Nrmin = 0.957 KWh/m3. These parameters can be used in practice when using the equipment for log extraction.