Phosphorus (P) is one of the most widely occurring nutrients for development and growth of wheat. In this study; the effects of P application amount on grain yield; protein content; and phosphorus use efficiency (PUE) were studied by agronomic management of P fertilizer on spring weak-gluten wheat (Triticum aestivum L.) grown under field conditions for  yr. The experiments were performed at five levels of PO application amount; including ; ; ; ; and  kg ha-. As a result; with increase in P fertilizer; grain yield; and P agricultural efficiency (AEP) increased in a quadratic equitation; but partial factor productivity of P (PFPP) decreased in a logarithmic eq. When  kg ha- PO was applied; the grain yield reached the highest level; but the protein content in gain was lower than .%; a threshold for the protein content to evaluate weak-gluten wheat suitable for production of cake and biscuit. Yangmai  and Ningmai  could tolerate to higher P level of soils than Yangmai  that had more loss in grain yield when P fertilizer was over-applied. AEP had a concomitant relationship with grain yield and was a better descriptor for P use efficiency in the wheat. A high P use efficiency resulted in leaf area index (LAI); increased chlorophyll content and photosynthetic rate; and stable acid phophatase (APase) activity to accumulate more dry matter after anthesis; which explained that the optimum P fertilizer increased grain yield and improved grain quality of weak-gluten wheat.