Abstract: Noise-jammer is a kind of acoustic countermeasure devices, which can be used to combat active and passive sonar searching. Based on the sonar equation, the parametric models of jamming effect of noise-jammer for active and passive sonar are provided respectively. The decrease rate of detection distance and the suppressing sector are analyzed and computed. An example of simulation analysis is given. The presented method can fast and effectively measure the jamming effect of noise-jammer and provide an important reference for the strategy and tactics of underwater acoustic warfare.