The invention discloses a device for automatically monitoring an indoor tap water pipeline and automatically closing the indoor tap water pipeline in case of water leakage. The device comprises a flow detection system, a mobile phone APP control system and an electromagnetic valve switching on and off system; the flow detection system comprises flow meters installed on a main pipeline and branch pipelines and is used for monitoring the flow in the main pipeline and the branch pipelines in real time, and when a reading of the flow meter of the main pipeline is unequal to the sum of readings of the flow meters of the branch pipelines and the single-time water consumption of one branch pipeline reaches a maximum value, the flow meter of the corresponding branch pipeline can send a monitoring result to the mobile phone APP control system; the mobile phone APP control system is used for outputting electromagnetic valve switching on and off control commands according to the monitoring result sent by the flow detection system; the electromagnetic valve switching on and off system is used for switching on and off an electromagnetic valve according to the control command output by the mobile phone APP control system. According to the device, automatic monitoring on the indoor tap water pipeline and automatic closing on the indoor tap water pipeline in case of water leakage can be achieved, and unnecessary hazards are greatly reduced.