*

Systematic pressure and doping dependent study on Mo_1-xW_xTe₂ was carried out to investigate the correlation among chemical doping, structural transition, and superconductivity. Doping dependent resistivity measurement at ambient pressure shows structural transition temperature (T_s) for MoTe₂ to be 249 K, which continuously increases as doping level (x) increases and reaches a maximum value of 613 K for WTe₂. The structural transition of WTe₂ at ambient pressure is also confirmed by conducting temperature dependent synchrotron X-ray diffraction from 300 K to 673 K. Three samples with different doping (x = 0.10, 0.40, 0.75) were selected for high pressure measurement. The superconducting transition temperature - pressure (T_c - P) phase diagrams have been constructed and will be discussed. Our experimental results revealed a competition between the structural transition and superconductivity in Mo_1-xW_xTe₂. Superconductivity emerges when the T_s is suppressed below 175 K and T_c increases as T_s is suppressed.