A proof of reciprocity relations for nonlinear systems ininhomogeneous variable electric and magnetic fields in the presence ofunsteady spin currents, thermodynamic flows and mechanical disturbances isobtained by the Kubo method in the approximation of Markov relaxation andlocally quasi-equilibrium distribution. Keywords: Nonlinear distributed systems, locally quasi-equilibrium distribution, Markov relaxation, spin current, reciprocity\

In the Markov relaxation and locally quasi-equilibrium distribution approximation, analogues of Onzager's relations for the response functions of the spin current in the nonlinear by intense mechanical and thermodynamic effects regime were obtained by the Kubo method. Keywords: locally quasi-equilibrium distribution, spin Hamiltonian, spin current, nonlinearity, reciprocity, streintronics, spin caloritronics, Peltier spin effect, Zeebeck spin effect.