Physical Layer Security (PLS) is becoming a hot topic in wireless communications research. The application of artificial noise can reduce the eavesdropping ability of illegal eavesdroppers without affecting legitimate users. Most current PLS schemes only consider static scenarios without taking mobility into account. Some Cooperative Jamming (CJ) schemes analyse the security performance in mobile scenarios, but do not exploit the handoff and cooperation of friendly jammers. To address the above challenge, we propose a CJ scheme for soft-handoff-based cooperative jamming (CJSH) in mobility scenarios. We first consider a common scenario where a base station communicates with a mobile legitimate user alongside a mobile passive eavesdropper. Some friendly jammers with multiple antennas are chosen to emit artificial noise. Next, we design two corresponding thresholds for jammer entry and exit and measure the values based on the Secrecy Outage Probability (SOP). We then define the Power Average Security Gain (PASG) as the system performance to balance security and energy consumption. Finally, numerical simulation results are provided to verify the rationality of the proposed handoff scheme and demonstrate that it effectively improves the system security performance and jamming power consumption.