The invention provides a full-band ship cabin noise prediction and acoustic optimization design method. The method comprises the steps that characteristic numbers are used as a frequency range dividing standard, according to geometric and physical properties of a ship structure and an acoustic cavity, the characteristic numbers are calculated, and based on the magnitude of the characteristic numbers, an analyzing frequency band is divided into low frequency, medium frequency and high frequency; according to the magnitude of the characteristic numbers and the characteristics of the ship structure, low-frequency, medium-frequency and high-frequency ship cabin noise prediction models are built; through real ship testing or an empirical formula, main power device structure noise and air noiseare obtained, and power device vibration acceleration is equivalent to exciting force; loss factors in the ship structure and the acoustic cavity are obtained through estimation; by using the finite element method, the finite element-statistical energy hybrid method and a statistical energy method, low-frequency, medium-frequency and high-frequency ship vibration and cabin noise of a ship are calculated; the medium-frequency noise and the high-frequency noise in the ship cabin are subjected to sound absorption and noise reducing research and acoustic optimization design. A full-band ship cabinnoise prediction process and a control scheme are provided, and the method can be used for various ships.