Abstract: High-quality nitrogen and organic carbon sources can greatly contribute to the microalgae growth in a parthenogenetic manner. Among them, the nitrogen and phosphorus-rich biogas slurry can combine with the hydrolyzed acidification products of the agricultural straw. Moreover, the straw can be expected to serve as an excellent substrate carrier for the microalgae attachment during cultivation, due to the naturally rough surface and porosity. Microalgae biomass can be used to improve the tolerance of the microalgae to complex environments. In this study, Kirchneriella obesa was taken as a research species. A systematic investigation was implemented to explore the growth and pollutant removal of the microalgae cultured in biogas slurry with straw addition. There was the high tolerance of the microalgae to high ammonia-nitrogen biogas slurry, low temperature, and low light intensity under parthenocarpic conditions. The results showed that the addition of the corn straw was significantly enhanced the biomass of suspended microalgae. The microalgae was also attached to the surface of the straw, in order to realize their tolerance to the high ammonia-nitrogen biogas slurry, low temperature, and low light intensity. There was the increase in the total biomass yield and the contents of lipids and carbohydrates in the microalgae. While the contents of proteins and chlorophyll were reduced significantly. Moreover, the microalgae of the nutrients were effectively removed from the biogas slurry and hydrolyzed acidification products of the corn straw. Once the biogas slurry was added at a concentration of 30%, the optimal total biomass yield and lipid content of the suspended and attached microalgae reached 2.81 g/L and 20.43%, respectively. At the same time, the removal rates of the total nitrogen, ammonia nitrogen, total phosphorus, and chemical oxygen demand (COD) were 87%, 88%, 95%, and 90%, respectively. The light intensity and aeration rate were reduced to 2 000 lx and 1.0 L/min, respectively. The relative abundances of Bacteroidota and Verrucomicrobiota were promoted the lignocellulosic hydrolysis and bacterial-microalgal symbiosis, as well as Dyadobacter. As such, the biogas slurry with the straw was greatly contributed to the secretion of the extracellular polymeric substances. However, Cyanobacteria almost disappeared during microalgae cultivation. The optimal process parameters were obtained through a 3-factor, 3-level orthogonal optimization test: with 28% biogas slurry addition amount, 4 310 lx light intensity, and 1.13 L/min aeration rate. While the optimal total microalgal biomass production only increased to 2.83 g/L. Additionally, the corn straw attached by microalgae can be directly used for the production of biofuels, and ruminant feed without the need for separation. Therefore, it is also feasible on the microalgae cultivation with the biogas slurry and the corn straw. The finding can provide a basis on the low-cost and straw microalgal cultivation, such as the biofuels and feed in cold regions.