The invention discloses a method for adjusting and controlling algal facies and water quality of an aquaculture pond in situ. The method comprises the following steps: a, kieselguhr powder with particle size of 200-1000 mesh is selected, and a compound microbial preparation is selected, wherein the bacterial population in 1 ml of the compound microbial preparation is greater than or equal to 100 million; b, when a base fertilizer and rich water are started to apply in the pond, the kieselguhr powder and the compound microbial preparation both obtained in step a are sprayed in the pond; c, after 15-20 days, the dissolved oxygen concentration and the ammonia concentration in the pond water are maintained at 5-9 mg/L and 0.1-0.4 mg/L respectively, the pond water is sandy beige, and the pond algal face is mainly alga of bacillariophyta observed through a microscope; d, offspring seeds of a to-be-cultivated target are put in the pond. Through the way, the method, disclosed by the invention, can improve the using effect of the microbial preparation commonly used in aquaculture, effectively adjusts and controls algal facies and water quality, reduces occurrences of diseases, and improves cultivation quality and quality of aquaculture products.