China Institute of Atomic Energy (CIAE) designed and built an accelerator-driven sub-critical reactor (VENUS 2). VENUS 2 consists of a water reactor core and a lead reactor core with different neutron spectrum. In two core schemes of VENUS 2, source multiplication method, jump-source method, pulsed neutron source method and are used to measure the sub-critical reactivity and study the influence of material reactivity in the central target area. The reactivity measurement at sub-critical state was carried out in VENUS 2 lead reactor using BF3 detector based on source multiplication method. The deviation of measurement results is less than 0.1% under shallow sub-critical condition. The subcriticality measurement was carried out in VENUS 2 lead reactor (keff ≈ 0.99, 0.98 and 0.97) based on jump-source method, the experimental deviation of three results was less than 4%. Based on the pulsed neutron source method, a D-T neutron generator was installed in the lead reactor core to measure the time decay curve under several subcriticality degrees, and the subcriticality degrees were obtained by fitting. Based on random pulsed neutron beam generated by neutron tube is controlled by external signal to realize reactivity measurement. The reactivity values of different target materials in the central target area were measured by jump-source method (keff ≈ 0.99) in VENUS 2 water core. The above experimental results are in good agreement with the theoretical calculation, which validates the sub-critical calculation method developed by CIAE, and has important significance for the subsequent engineering design.