The invention relates to a direct-current electronic load and especially relates to a direct-current constant-resistance electronic load apparatus. By using the apparatus, operation is simple; manual adjustment is not needed; and accuracy and precision are high. The apparatus is characterized in that the apparatus is formed by a voltage acquisition circuit, a signal conditioning circuit, a voltage maintenance circuit, a load driving circuit and a simulation load circuit; the voltage acquisition circuit collects a detected power supply output voltage; a voltage signal acquired through sampling is processed by the signal conditioning circuit so as to adapt to a load driving circuit signal requirement; the conditioning circuit outputs to the voltage maintenance circuit so as to carry out voltage maintenance; the voltage maintenance circuit outputs to the load driving circuit; and the driving circuit outputs to a control terminal of the simulation load circuit. Compared to the prior art, by using the apparatus of the invention, the electronic load can realize a constant-resistance mode; and the circuit possesses characteristics that the structure is simple, real-time following performance is realized, linearity is good and so on.