In view of the limitation of the range factor on analyzing low probability of intercept (LPI) performance of MIMO radar systems, a performance parameter is derived and applied for quantifying the LPI performance of distributed MIMO radar systems. A series of contour charts have been given with different values of geometrical parameter. By plotting and analyzing these charts, the LPI performance can be obtained intuitively. Simulation results show that LPI performance of distributed MIMO radar systems depends on both radar parameter and system geometry. It is shown that the spatial diversity gain plays an important role in designing a distributed MIMO radar system with robust LPI performance.