Carrier injection performed in oxygen-deficient YBa2Cu3O7-δ (YBCO) hetero-structure junctions exhibits tun-able resistance that is entirely different from the behaviour of semiconductor devices. Tunable superconductivity in YBCO junctions, increasing over 20 K in transition temperature, has achieved by using electric processes. To our knowledge, this is the first observation that intrinsic property of high Tc superconductors superconductiv-ity can be adjusted as tunable functional parameters of devices. The fantastic phenomenon caused by carrier injection is discussed based on a proposed charge carrier self-trapping model and BCS theory.