The article presents a method for solving the problem, eliminating the oscillations of the load on the knuckle join suspension the simultaneous movement of two elements of the boom system, namely, lifting the jib and movement the telescopic section. The essence of the method is based on the optimization of the regime of simultaneous movement of two elements of the boom system of the loader crane during horizontal movement of the load during the start-up period. As an optimization criterion, a complex integral criterion was selected, which is a relative root-mean-square value of forces and powers in hydraulic drive cylinders. The developed criterion displays the undesirable properties of the boom system elements and drives mechanism, therefore, its values are minimized. Since the optimization criterion is an integral functional, variational calculus method are used to optimize it. The solution of the variational optimization problem is presented in the form of many parametric functions that satisfy the boundary conditions of motion and minimize the complex dimensionless criterion. For this purpose, the particle swarm optimization method (ME-PSO) was used. This made it possible to obtain the dependences of the optimal, energy and forces characteristics of the boom system and the drive mechanisms of the crane. The mode of movement of the boom system elements obtained as a result of optimization improved the forces and energy characteristics of the loader crane, which made it possible to increase its reliability and productivity.