Wave-guiding in phononic crystal has been typically achieved by imposing a crystal defect having different geometry or material. This paper presents active wave-guiding of piezoelectric phononic crystal by external electrical control. Unlike existing waveguides, the present method would require relatively simple structures because no permanent geometry or material change is required and because somewhat arbitrarily shaped waveguides can be formed actively in the phononic crystal structure. By the finite element analysis, it is shown that waves in the phononic crystal can be guided through the desired direction if piezoelectric inclusions in the phononic crystal are electrically controlled. Several simulations show the feasibility of the suggested method and the related physics of the waveguide are explained by the analysis with a supercell.