Abstract: Disclosed is a method for preparing acetaldehyde from acetylene under the catalysis of a ZAPO molecular sieve. The method comprises the steps of pre-heating an acetylene raw material gas and water, subjecting same to continuous hydration in a fluidized bed under the catalysis of the ZAPO molecular sieve to prepare acetaldehyde, and then subjecting same to separation, absorption and rectification to obtain an acetaldehyde product, wherein the catalyst can be continuously regenerated for use. The process of the present application is simple, stable and efficient, solves the problem of the dependence nature of the production of acetaldehyde by means of acetylene hydration on a mercury catalyst, avoids the harm caused by mercury to the human body and the environment, and has higher production and use values.