Abstract: This paper approaches equilibrium problem of ladder. Friction forces at two ends of ladder are considered. It is a static indeterminate and nonlinear problem.. Functional relation between two coefficients of friction at the ends of ladder is deduced. Stability of equilibrium of ladder is discussed. Value domain of two normal constraint reactions at ends of ladder is determined. Relation among normal constraint reactions and coefficients of friction and position parameters of ladder is found. Formulas of critical inclination of ladder and allowable height of active force are deduced.