The invention relates to a method for preparing a preserved beancurd product, which belongs to the production field of the preserved beancurds. Primary fermentation and after fermentation are the key steps. The production process of the preserved beancurd comprises the following steps: soybean soaking, jordaning, filtering, warming, refiltration, defoaming, adding coagulant and blank forming, dicing, inoculating, primary fermentation, pickling, bottling, adding soup, covering and after fermentation. The raw materials of GMO free and green food are that protein contained in the soy bean is more than or equal to 38%, slag contained in the soy milk is less than or equal to 15%, crude protein contained in the bean dregs is less than or equal to 28%, and the final temperature of the soy milk in the final siruping tank of overflow tanks is more than or equal to 90 DEG C. When the jellied bean curd is 50%, turning over is carried out slowly and the flow rate of the coagulant is reduced, and when the jellied bean curd is 80%, turning over and the flow of the coagulant are stopped for standing statically; the squeezing is carried out at 8-10Mpa, the moisture content of white blank is 66-73%, the inoculation is carried out at the temperature of 40 DEG C, the primary fermentation is carried out for 36-48 hours and cages are exchanged for three times, and the first exchange, the second exchange and the third exchange are carried out respectively at the temperature of 23-28 DEG C, 22-26 DEG C and 18-22 DEG C. wherein, the relative humidity in the three exchanges are all 60%; pickling is carried out for 3-5 days, then after fermentation is carried out at the temperature of 15-30 DEG C for 45-60 days, and the finished product contains 3.5-18% of salt. The method of the invention can be used for preparing the preserved beancurd.