The invention discloses a low-voltage and high-current reversing device based on an H bridge, relates to the field of current reversing, and aims at solving the problems of an existing current reversing circuit that the reversing speed is not enough, and the relay conversion switch generates noise when the high current passes through. A positive electrode of a constant current source is connected with a positive electrode of an H bridge converting circuit, a negative electrode of the constant current source is connected with a negative electrode of the H bridge converting circuit, one signal output end of the H bridge converting circuit is connected with one end of a load, the other signal output end of the H bridge converting circuit is connected with the other end of the load, and the H bridge is built by a solid state relay. Compared with a common relay, according to the parameter of the solid state relay, the speed of the solid state relay is further higher than the speed of the relay, the noise is avoided when the switch is switched, and the solid state relay has no noise problem compared with the common relay. The saturation voltage drop of the H bridge is small, the current reversing speed is high, the reversing function is realized within 5ms, the absolute values before and after current reversing are constant, and the output is stable. The device is suitable for the field of current reversing.