Considering the scenario of multiple targets equipped with interceptors in the modern electronic warfare environment, an LPI-based Resource Allocation Strategy (LPIRAS) for multiple targets tracking (MTT) in collocated MIMO (CMIMO) radar is proposed in this paper, where subarray number is exploited in the low probability of intercept (LPI) optimization problem for the first time. As the problem is formulated as a nonconvex and nonlinear optimization problem, the array power, target-beam assignment, subarray number, and subarray-beam assignment are corporately managed through a methodology incorporating the two-stage search algorithm (TSA), permutation-based target swarm generation algorithm (PTSGA) and adaptive extra subarray assignment algorithm (AESAA), resulting the LPIRAS. Finally, numerical simulations show the proposed strategy is effective and real-time. In comparison to other benchmarks, the LPIRAS achieves superior LPI performance.