Small-scale hydraulic automatic biological filtration process

The invention relates to a small-scale hydraulic automatic biological filtration process comprising a plurality of operation cycles, wherein each operation cycle comprises a filter process and a backwash process. The filter process is realized by the steps that: raw water or puddle water to be treated is injected into a raw water tank of a small-sized hydraulic automatic biological filtration device, then enters a siphon raising pipe, flows downwards into a quartz sand column, sequentially passes through a biological activated carbon column and a nano metal cluster column, enters a backwash water tank and finally enters a water outlet water tank to obtain purified water; the backwash process is realized by the steps that: water current from the backwash water tank sequentially enters the biological activated carbon column and the quartz sand column for back washing when the water level of the raw water or puddle water to be treated in the siphon raising pipe rises to a pipe mouth of a siphon auxiliary pipe; and the backwash process is ended and the filter process is recovered when water level of the backwash water tank decreased to a siphon damage head. The small-scale hydraulic automatic biological filtration process is simple for operation, has remarkable effect for removing pollutants and is applicable to water quality treatment of water collecting puddle water in villages and towns in northwest of China.