The influences of controlled over-pressure sintering on the critical current density and mechanical properties of the Bi-2223/Ag high-temperature superconducting tape have been investigated. XRD and SEM were used to analyze the reasons of the improvement of the tape’s properties. The results show that the critical current density of the tape is promoted by more than 30% while the tensile strength and critical bending strain are improved to 104 MPa and 0.91% respectively. The Bi-2223 content is increased and the FWMH value of the tape is lowered from 6.5° to 5.6° by the controlled over-pressure sintering process. Besides, the densities of the ceramic cores are improved. Due to the higher Bi-2223 content, better grain alignment and higher core density, the critical current density and mechanical property are improved