  An analytical theory to calculate the dissipatively stable concurrence in the
system of two coupled flux superconducting qubits in the strong driving field
is developed. The conditions for the entanglement state generation and
destruction during the formation of the multiphoton transitions regions due to
the interference of Landau--Zener--St\"uckelberg--Majorana are found. Based on
the solution of the Floquet--Markov equation, the technique is proposed to
adjust the amplitudes of dc- and ac-fields for effective control of the
entanglement between qubit states while taking into account the effects of the
decoherence.
