For the purpose of enhancing the desalination performance, a desalting layer was successfully constructed on a cellulose acetate (CA) virgin membrane via acetalized surface crosslinking treatment. The acetalization crosslinking reaction consists of two hydroxyl groups reacting with one aldehyde group to remove one molecule of water. Results showed that the reaction occurred on the surface of the CA membrane, as measured by Fourier-transform infrared (FTIR), differential scanning calorimeter (DSC), X-ray photoelectron spectroscopy (XPS), and scanning electron microscope (SEM). The water flux and desalination performance were compared before and after crosslinking, and the formation of the desalting layer greatly improved the desalination performance of the membrane. In addition, the crosslinking temperature, crosslinking time, and formaldehyde solution mass fraction of the CA membrane structure and performance were explored. It was observed that the CA flat membrane showed better desalination performance, with a salt rejection rate of 98.55% and a water flux of 9.88 L/(m(2)center dot h), under a processing temperature of 100 degrees C 11% formaldehyde solution mass fraction and a crosslinking time of 60 min. POLYM. ENG. SCI., 59:913-918, 2019. (c) 2018 Society of Plastics Engineers