I have a makefile project. I know that in Eclipse CDT is possible to load makefile project.
Is it possibile to load it in qtcreator?
Yes and no. Choose: File->New File or Project...->Import Project->Import existing Project.
Imports existing projects that do not use qmake, CMake or Autotools. This allows you to use Qt Creator as a code editor.
It is really the last choice, but you can load a Makefile project into QtCreator. How well it works... hard to say. Depends on the project and how the Makefile is created. Most likely you can compile your project. Editing files: Probably no problem. But adding new files... I don't think QtCreator can handle Makefile changes.