Aiming at the application of natural objects false target in laser decoy jamming, its deceiving ability characterized by decoy airspace was calculated and analyzed. On the premise of full considering the reflection characteristics of target, the intensity of jamming-indicating laser, atmospheric laser attenuation coefficient, and other factors, the analysis model of decoy jamming ability for false target was established under the condition of suppression coefficient K (≥1). Furthermore, the effectual decoy airspace of common natural objects was analyzed under typical condition. The results show that the effective cheating airspace of false target is closely related to the type of targets, and the deceiving ability of vegetation, gravel and diffuse reflection objects is enhanced in turn under the same conditions. There exists a mirror reflection component that is much smaller than the diffuse reflection component in the decoy airspace of vegetation and gravel natural objects, and the variation of the incident angle of jamming laser has obvious influence on the distribution of effectual decoy airspace. However, there is no obvious trend change rule for the decoy airspace of vegetation targets with the incidence angle. The research results are instructive for the reasonable application of typical natural objects used for false target.