Plants absorb and transport phosphorus through phosphorus transporters, and sufficient phosphorus can improve crop yield, quality, and stress resistance. High temperature is an important environmental factor affecting the growth and development of potato. In this study, we overexpressed the phosphorus transporter StPHO1.2 in potato mediated by Agrobacterium tumefaciens, and then compared the growth of transgenic strains and wild-type strains at high temperature (35℃) and normal temperature (22℃±1℃). The results showed that overexpression of StPHO1.2 could improve the heat resistance and promote the growth of potato. And the higher the phosphorus concentration, the stronger the resistance, the better the growth. Subcellular localization in tobacco showed that StPHO1.2 was expressed on cell membrane. Therefore, the membrane system library plasmid was selected to screen the interacting proteins of StPHO1.2. This study demonstrated that the phosphorus transporter StPHO1.2 interacted with both the calcium ion transporter associated protein (StCAX1) and the photosynthetic system II protein subunit (StPsbR) by the yeast two-hybrid and BiFC. In conclusion, overexpression of StPHO1.2 may improve the heat tolerance and promote the growth of potato by affecting photosynthesis and signal transduction in potato. These results provide theoretical basis and reference for further understanding of the function of phosphorus transporters and promote the breeding of new potato varieties.