In this article, a good-quality crystal Yb:YAG was grown by pull method, and its absorption spectrum of 200-3000 nm was measured at room temperature. Its absorption of 200-300 nm is from the host YAG, and there exists only the characteristic absorption of Yb3+ in the range of 390-3000 nm. Judd-Ofelt theory computation indicates that the absorption and emission oscillator strengths of electric dipole of (24 at%) Yb:YAG are 3.58 x 10(-6) and 4.77 x 10(-6), respectively, and the absorption and emission transition probabilities are 879 and 1171/s respectively. As for magnetic dipole, the absorption and emission oscillator strengths are 3.32 x 10(-7) and 4.43 x 10(-7) respectively, and the absorption and emission transition probabilities are 82 and 109/s respectively. The lifetime of the energy level2 F(5/2) is 781 micros.