The invention discloses a reconfigurable optical differential equation set solver. The solver comprises a plurality of optical resonant cavities, a beam combiner, a beam splitter, an input waveguide, an output waveguide and a feedback waveguide. One or more paths of optical pulses are input as independent variables, and a plurality of paths of optical pulses are output as dependent variables. According to the solver, the feedback waveguide is imported between cascade optical resonators so as to realize the mutual coupling between different variables and then construct and solve complicated ordinary differential equation sets. Through adjusting coupling coefficients in coupling areas of the optical resonant cavities, a light combining ratio of the beam combiner and a light splitting ratio of the beam splitter, coefficients of equations are adjusted to realize different forms of differential equation sets or different orders of differential equations. The solver disclosed by the invention is simple in structure, good in extendibility and high in working speed; and by utilizing the existing processing technology, the solver is small in volume, low in power consumption and easy to be integrated with electric elements, and is expected to be applied in future high-speed optical calculation speeds.