Multi-stage auxiliary sampling device for DNA (deoxyribonucleic acid) sample in water environment

The utility model provides a water body environment DNA sample multistage auxiliary sampling device which comprises a leakage bottle, a collecting bottle, a vacuumizing device and a plurality of sampling devices with different filtering aperture specifications, the collecting bottle is arranged at the bottom, the plurality of sampling devices are connected end to end and are sequentially and vertically stacked at the upper end of the collecting bottle according to the filtering aperture specifications from small to large, and the vacuumizing device is arranged on the collecting bottle. The leakage bottle is arranged at the top of the sampling device on the uppermost layer, a water outlet of the leakage bottle faces downwards and directly faces the sampling device, the multiple sampling devices are connected with the collecting bottle and the leakage bottle in a sealed mode, inner cavities of the sampling devices are communicated with one another, and an exhaust pipe communicated with the inner cavity of the c