The invention relates to a preparation method of a nanofiltration membrane by a particle packing method, belonging to the field of inorganic membrane preparation. The method adopts aluminium oxide fine powder with a certain particle size to carry out filling pretreatment to a ceramic support body, and achieves the purpose of modifying the surface of the support body and inner pore diameter, thus improving the membrane-making quality of the post stage and simplifying the preparation technique. The invention shortens the technique steps from 15 to 21 steps for repeating the steps of coating, drying and hot treatment for 5 to 7 times in the traditional membrane-making technique by a sol-gel method to the 10 steps and shortens the period from 30 days to 10 to 12 days.