The invention relates to an in-situ synthesized TiCx-Ni3(Al,Ti)/Ni-based gradient composite material and a hot-pressing preparation method thereof. The in-situ synthesized TiCx-Ni3(Al,Ti)/Ni-based gradient composite material uses Ti3AlC2 and Ni-based alloy as the raw materials, and in-situ reaction is performed in each layer to generate the TiCx and Ni3(Al,Ti) enhanced Ni-based composite material.The ceramic phase of the whole gradient is in continuous transition, no evident interface exits between layers, and the layers are firmly combined; as the increasing of the content of Ti3AlC2, TiCx and Ni3(Al,Ti) gradually increase, hardness gradually increases, and the requirement for changing from structure transition to performance transition is satisfied. The preparation method includes: adding the different-proportion mixed powder of Ti3AlC2 and Ni-based alloy into a hot-pressing mould layer by layer, heating to 1000-1400 DEG C at the heating speed of 10-20 DEG C/minute, applying the pressure of 25-30MPa, keeping the temperature and the pressure for 30-60 minutes to allow the mixed powder to have sufficient reaction and compacting, and cooling to obtain the TiCx-Ni3(Al,Ti)/Ni-based gradient composite material. The material is widely applicable to fields such as aerospace, war industry, machine manufacturing and nuclear energy which requires high surface hardness, high surface wear resistance and high surface temperature resistance and has high temperature differences and thermal shock.