Pseudo-ternary CrP4-type (V,Cr,Mo)P4 was successfully synthesized at the conditions of 4 GPa and 900 °C by using a large volume multi-anvil-type press. SEM-EDS and STEM analyses revealed that the synthesized pseudo-ternary (V,Cr,Mo)P4 contains almost equimolar amounts of transition metals. The lattice parameters and unit cell volume of (V,Cr,Mo)P4 yield the average value of its end-members. The low-temperature (133 K–333 K) in-situ synchrotron XRD measurements demonstrated that the c-axis showed the highest coefficient of thermal expansion, followed by the b-axis and the a-axis. These thermal behaviors are the same as the binary end-members and pseudo-binary (V,Cr)P4. While from the high-pressure (P < 10 GPa) in-situ synchrotron XRD measurements, it was found that (V,Cr,Mo)P4 showed no phase transition and compression behaviors in which the c-axis was more compressible than the other two axes (b and a) and the b-axis was slightly compressible more than the a-axis. The zero-pressure bulk modulus of 106 (1) GPa and 122.1 (7) GPa were obtained for (V,Cr)P4 and (V,Cr,Mo)P4, respectively. MoP6 octahedral is highly distorted in comparison with VP4 and CrP4, thus the incorporation of MoP4 greatly yields incompressible behaviors of CrP4-type phosphides with respect to temperature and pressure.