The invention belongs to a binary angle quantity signal converting system and method based on a digital circuit, relates to the technical field of angle signals. In adoption of the method and the system provided by the invention, binary angle quantity can be converted into orthogonal increment pulses. The scheme provided by the invention is that an accumulator and a comparer are designed for storing an internal state angle and comparing the magnitude of the internal state angle and an input angle; through comparing the magnitude of the input angle and the internal state angle, the internal state angle quantity is gradually increased or reduced to the state the same to the input angle; orthogonal increment pulses are calculated in the change process of the internal state angle; through the conversion technique, the binary digital angle quantity can be converted into the orthogonal increment pulses; in adoption of the technique, the drive capabilities of some motor drivers incapable of using rotary transformers can be improved; R/D solution is carried out to the output signals of the rotary transformers; further angle quantity/orthogonal increment pulse conversion is carried out; and the drivers can be compatible with the rotary transformers.