The invention discloses a recycling utilization method of biochemical sludge. The recycling utilization method comprises following steps: 1, biochemical sludge is subjected to drying, calcining, and smashing so as to obtain aluminum ash powder; 2, industrial hydrochloric acid and water are added into the aluminum ash powder for acid dissolving; 3, a polymeric flocculant is added for flocculent precipitation, filtering is carried out so as to obtain harmless sludge and a filtrate I, a heavy metal trapping agent is added into the filtrate I, an obtained mixture is allowed to stand, a supernate is removed, obtained bottom heavy metal sludge is collected, and heavy metal in the bottom heavy metal sludge is recycled; 4, aluminum powder is added into the surpernate obtained via step 3, full reaction is carried out, filtering is carried out, an obtained filter cake I is washed with water so as to obtain a filtrate II and a filter cake II, the filter cake II is used for preparing bricks, and the filtrate II is subjected to low temperature curing so as to obtain polymeric aluminium chloride. The recycling utilization method is simple in processing technology, and low in cost, is capable of saving energy, and is friendly to the environment; the processed biochemical sludge can be directly applied in agricultural production or brickmaking; no secondary pollution is caused; and sewage treatment agent polymeric aluminium chloride can be recycled.