The invention discloses an intelligent monitoring data box and monitoring system for tap water pipelines. The data box is arranged at the rear end of a water meter and comprises three modules: a purification module, a data module and a control module, wherein the purification module comprises sterilizing and water quality purification devices; the data module comprises an inlet and outlet water quality and flow sensor and an information PCB controller; the control module comprises an electromagnetic valve, a water quantity controller and a temperature controller. The working principle of the system is as follows: tap water is purified in the purification module, water quality is simultaneously detected, detection data is sent to a cloud platform through the information PCB controller, andthe cloud platform sends information of operation, water quality, use habits and the like of a tap water system to residential users everyday; the information PCB controller automatically switches offthe electromagnetic valve when water leakage happens. According to the monitoring system disclosed by the invention, sterilizing, purifying water, preventing water leakage, collecting tape water pipeline system information and the like are integrated, real-time operation, monitoring and management can be performed on an urban water supply system, and an internet of things function that objects are connected with each other is achieved.