The invention relates to a multistage suspension melting crystallization method for separating p-xylene. The multistage suspension melting crystallization method comprises the following steps: carrying out shunt operation on raw materials, carrying out multistage crystallization on a part of the raw materials, directly obtaining a p-xylene product, then using the rest of the raw materials to carry out pulping washing and warming aging on a low-temperature crystal in an aging kettle, and obtaining residual p-xylene product. Stable operation of the aging kettle is guaranteed by adjusting the amount and temperature of the raw materials entering into the aging kettle, and then the stability of product purity and yield is guaranteed. Through the technical scheme adopted in the invention, the problems of unstable operation of the aging kettle and high energy consumption existing in the prior art are preferably solved, and the method can be used in the crystallization production of the p-xylene.