The invention discloses an ultralow-power-consumption pH signal conditioning transmission circuit and a real-time water quality monitoring system. The monitoring system comprises a pH sensor, a smalllightweight portable box, a lithium iron phosphate battery box, the pH signal conditioning transmission circuit, a single chip microcomputer, a data receiving module, an analog-digital conversion module and a data transmission module is arranged in the portable box. Under 3V power supply of a single power supply, power consumption of the pH signal conditioning transmission circuit can reach an ultralow state of 130mu A or less; furthermore, -414mV(ph=14) to +414mV(pH=0) weak water quality parameter signals monitored by the pH sensor can be correspondingly amplified to 1.4V to 0V, so that the real-time water quality monitoring system can reach ultralow power consumption, can be conveniently installed at different detection sites especially in inspection wells without achieving power supply,can be applied to monitoring whether sewage and wastewater meet a discharge standard and can report the abnormal water quality situations in time; thus, the problem that real-time collection cannot be achieved mutually in real life and the problem of long-time power supply of the system are solved, manpower resources are saved, and cost is reduced.