To clarify the effect of sensor allocation form and the number of sensors on the localization precision, the localization performance of sample mean in multi-sensor triangulation localization is analyzed in the global coordinate system. First, the correlation between intersections and the Chebyshev condition is studied according to the consistency definition, which indicates that the sample mean in multi-sensor triangulation localization is a kind of inconsistency estimator. Second, combined with the effect of sensor allocation form on the localization precision, the approximate consistency condition of sample mean is analyzed. Finally, the relationship between consistency and multi-sensor localization precision, and the essential difference about consistency in the regular and irregular sensor allocation form are discussed respectively. Simulation results verify the analysis about the localization performance of the sample mean, which can be applied to multi-sensor passive localization algorithms based on sensor management.