For the mathematical model of a three-sector economic cluster, an optimal control problem is posed on an infinite time interval. An optimal stabilization problem is considered for a single class of nonlinear systems with coefficients depending on the state of the control object with constraints on control. A non-linear stabilizing control has been found taking into account constraints to the control, which depends on the state of the system and the current point in time. The results obtained for a nonlinear system are used in the construction of control parameters for a threesector economic cluster over an infinite time interval. For the considering example, the optimal distribution of labor and investment resources has been determined, which satisfy the balance ratios. The given example illustrates the use of the proposing control method of a nonlinear system.