The invention discloses a method for preparing 
virus of porcine reproductive and respiratory syndrome on a large scale. In the method, the 
virus of the porcine reproductive and respiratory syndrome is prepared in a 
cell microcarrier suspension culture system by a 
bioreactor. The method comprises the following steps of: inoculating host cells for preparing the 
virus to a carrier tank containing culture solution and a 
microcarrier, and mixing the cells and the 
microcarrier uniformly to ensure that the cells are attached to the microcarrier; providing sufficient nutrients and appropriate gas environment for the cells under the appropriate 
culture environment to ensure that the cells are grown until the cells are in an amount which are 10 to 20 times of the 
inoculation concentration on the microcarrier; preparing 
virus suspension from the virus of the porcine reproductive and respiratory syndrome by using 
cell maintenance culture solution to ensure that the suspension is adsorbed to the cells; culturing the virus under the appropriate 
culture environment; culturing continuously for 2 to 3 days to obtain virus solution; and after the virus solution passes inspection, performing 
freeze thawing on the virus solution twice at the temperature of -20 DEG C, and inactivating and purifying to prepare an 
inactivated vaccine of the porcine reproductive and respiratory syndrome or adding a freeze-
drying protective agent for 
freeze drying to prepare a live vaccine of the porcine reproductive and respiratory syndrome. The method has large production scale, high yield of single batch and low production cost.