This invention discloses an active soft border sound screen including: a passive sound screen, a secondary sound source array, an error sensor array and a controller, in which, the secondary sound source array is mounted at the top of the passive sound screen, the error sensor array is distributed near the secondary sound source. The optimum position for placing the error sensor is got by changing the placing position of the error sensor in digit simulation and experiment. The placing position of error sensor in the invention can make active soft border sound screen has good noise-reducing effect.