This paper considers the sound radiation characteristics of a cracked rectangular vibrating plate, varying the orientation angle of a line crack. The vibration response of the cracked vibrating plate is obtained by using ANSYS, the acoustic theory based on the lumped parameter model is used to calculate radiated sound power. The radiated sound powers are computed with varying the orientation angle of the crack: i.e, 0$^{circ}$, 45$^{circ}$, and 90$^{circ}$. It is found that characteristics of the radiated sound power are very closely related to the crack orientation, vibration mode and crack location.