A scan driving circuit includes a plurality of shift register units in cascade connection with each other. Each shift register unit includes a signal input end for receiving a first clock signal, a second clock signal, and an input signal. Each shift register unit further includes a signal output end for outputting an output signal. The output signal of one of the shift register units of a previous stage serves as the input signal of another shift register unit of a next stage. Each shift register unit adjusts an effective time length of the output signal by using duty cycles of the first clock signal and the second clock signal. An organic light-emitting display device includes an array substrate. The array substrate includes a pixel unit array, a data driving circuit, the scan driving circuit, at least one data line, and at least one scan line.
