This paper describes new evaluation formulas of ultimate strength and rotation angle for unbonded post-tensioned precast concrete beams. These formulas are composed by two main variables, one is a reinforcement index(q) and the other is an effective prestressing level(λ_pe). To evaluate coefficients of the evaluation formulas, we carried out a parametric study with a numerical section analysis model, and obtained regression formulas for the coefficients. By applying the evaluation formulas to the results of parametric study and experiments on the past, we elucidate that the formulas evaluate the ultimate strengths and rotation angles of them accurately.