The invention discloses a flocculation apparatus used for preservation of marine feed microalgae. The apparatus comprises a tank body, an accommodating cavity is arranged in the tank body, a stirrer is arranged in the accommodating cavity, the inner wall of the tank body is provided with a track strip, an interlocking bar is in rotating connection with slip strips, two ends of every slip strip are provided with rollers, the rollers slide on the track strips, every track strip is provided with a gap for the rollers to enter, the inner wall of the tank body is provided with a mounting plate, the mounting plate is provided with a driven gear engaged with a toothed disc, the driven wheel is provided with a dialing piece, the roller at one end of the slip strip moves to the gap and is pushed into the gap by the dialing piece, then the roller at the other end of the slip strip is in contact with the track strip, every slip strip is provided with an auxiliary stirring blade, a liquid separation tube used for sucking out an upper liquid obtained after liquid separation is also arranged in the tank body, and a part of the liquid separation tube traversing out of the tank body is connected with a suction pump. The apparatus adopting the above technical scheme makes the liquid at the edge be well mixed in order to guarantee the flocculation effect.