Orientation of solar absorber is an important factor to achieve high efficiency of thin film solar cells. In the case of Zn3P2 which is a promising absorber of low-cost and high-efficiency solar cells, (110)/(001) orientation was only reported in previous studies. We have successfully prepared (101)-oriented Zn3P2 films by phosphidation of (0001)-oriented Zn films at 350 degrees C. The phosphidation mechanism of Zn is discussed through STEM observations on the partially-reacted sample and the consideration of the relationship between the crystal structures of Zn and Zn3P2. We revealed that (0001)-oriented Zn led to nucleation of (101)-oriented Zn3P2 due to the similarity in atomic arrangement between Zn and Zn3P2. The electrical resistivity of the (101)-oriented Zn3P2 film was lower than those of (110)/(001)-oriented films, which is an advantage of the phosphidation technique to the growth processes in previous works. The results in this study demonstrated that well-conductive Zn3P2 films could be obtained by controlling orientations of crystal grains, and provide a guiding principle for microstructure control in absorber materials.