The present invention provides a method for determining the physiological state of a microbial community, which rapidly and precisely determines the physiological state of a microbial community present in a treatment tank of a wastewater biological treatment facility; and a wastewater treatment method utilizing the same. In the method for determining the physiological state of a microbial community of the present invention, the method includes the steps of staining the microbial community collected from a treatment tank of a wastewater biological treatment facility with a first fluorescent dye which binds to a nucleotide chain of a microbe in the microbial community, and a second fluorescent dye which is degraded by an enzyme in cells of the microbe to emit fluorescent light having a wavelength different from that of the first fluorescent dye; measuring a first fluorescent intensity (F1) derived from the first fluorescent dye and a second fluorescent intensity (F2) derived from the second fluorescent dye, regarding the stained microbial community; and determining the satisfactory degree of the physiological state of the microbial community.