Aiming at the condition that the over-the-horizon target is difficult to locate under the influence of tropospheric scattering and the earth's curvature, passive location model of OTH based on double stations cross location is researched in this paper. A calculation model of spherical cross location based on troposcatter is deduced by analyzing the characteristics of the propagation of the OTH target signal in the troposphere. Finally, the error analysis was given between spherical cross location and traditional plane cross location. The simulation result shows that the localization error of spherical cross location and traditional plane cross location can be ignored basically in the level of hundreds of kilometers for OTH target location.