The existing magnetic field energy collector standard energy management circuit has advantages of low efficiency, high power consumption, and high input threshold power. When the transformer collects weak magnetic field energy, it is difficult to drive the multicore cable monitoring system. To address the above issues, this article proposes a low-power and multi-core cable weak magnetic field energy collection management circuit principle of intermittently charging discharge. A low-power intermittent control circuit for selfpowered power supply is designed to greatly reduce power consumption. This circuit is comparable to the energy conversion efficiency of the management circuit through self-power supply variable frequency matching. The experimental results show that when the three-core cable passes the AC power of 40 A and 50 Hz, the output power of the magnetic field energy collector is 3. 3 mW, the maximum output power of the management circuit can reach 2. 45 mW, the maximum efficiency is 74. 24% , which is higher than the standard energy collection management circuit 6. 9 times. The proposed high-power self-power supply control circuit to meet the minimum average power consumption of the startup threshold is only 1. 52 μW, which is only 5. 93% of the control circuit power consumption with auxiliary power supply. This high-efficiency management circuit can be used not only for the weak energy collection of multi-core cables, but also for weak emotional magnetic field energy management such as the weak cable peripheral magnetic field, electromagnetic vibration energy collector, and reverse scattering sensor network caused by armor shielding.