An embodiment of the disclosure provides an electrochemical catalyst composite and a method of producing the same. The electrochemical catalyst composite according to an embodiment of the disclosure is a hybrid material having a heterojunction structure between metal phosphide with controlled crystal strain and the MXene, in which metal phosphide produced by a synergy effect between the two materials prevents an overlapping phenomenon caused by the van der Waals force of the two-dimensional MXene material and increases a surface area, thereby having an effect on increasing reaction active points. Further, metal phosphide material with the controlled strain causes an electron structure of an element in the MXene support to be rearranged, thereby inducing change in an electrical structure. In addition, the MXene support combined with metal phosphide having the controlled strain promotes a hydrogen generation reaction, thereby having effects on enhancing the electrochemical performance and improving the electrical properties and stability of the material.