With the development of microelectronic technology, people pay more and more attention to the security of integrated circuits. As the main resistance for chip anti-invasive attacks, the security of active shield (AS) is concerned with the information security of integrated circuits. In this study, a random reconstruction circuit based on Galois ring oscillator was designed to improve the security level of AS. First, by inserting reconfigurable nodes into AS, the connection relationship between channels of the AS could be changed randomly. The complexity of the shield could be increased and the failure area could be reduced, which led to the effective resistance of the rerouting attack. Then, a Galois-type true random number generator was designed by reusing the reconfigurable nodes, which solved the problem that the state of the AS was consistent after each power-up and further improved the security of the shield. An experiment was designed and conducted based on the eight-channel AS. Simulation results show that the reconfigurable nodes in this study were only 4 395 μm² using SMIC 0.18 μm process technology. The insertion of reconfigurable nodes only increased the power consumption by 0.4%, and the maximum failure area of the AS was 80% smaller. Random bit stream generated using true random number seeds passed NIST SP800-22 tests. The design circuit has the advantages of small resources occupancy and low power consumption, and it can be combined with a multi-channel AS to provide a higher level of security protection for the chip.