The invention discloses a method for judging vacuum freeze-drying end points. When the temperature of materials at a primary (secondary) drying stage is close to that of a shelf, a separation valve t2 between a drying chamber and a cold trap is periodically closed every t1 minute, a dew point rise value is measured, finishing of primary (secondary) drying is judged if the dew point rise value is equivalent to that in idle load. Otherwise, drying is continued until the dew point rise value is equivalent to that in idle load, and then primary (secondary) drying is finished. The method can be used for reflecting drying conditions of samples in batch, process change is obvious, the freeze-drying end points can be accurately judged, freeze-drying time is saved, and energy consumption is reduced.