The invention provides a method and system for improving power consumption information transmission efficiency in a power line carrier communication network. According to the method, a unique short address is allocated to each node in the system; a response time slot of each node is confirmed according to the short address; and each node automatically reports a response data message in the node within own response time slot. The problem that the monitoring efficiency is low, the signal collision is serious and the data transmission efficiency is low in a power line carrier communication network is solved. According to the method, each node collects corresponding data and reads relay data needing to be reported in advance through utilization of the time of waiting for the response time slot and packages and caches the data before the response time slot arrives. An original process of reporting and forwarding required data and collected data step by step for the data of each ammeter is eliminated. All data collection and reading processes are uniformly scheduled to be processed in non-response time slots. The data in the power line carrier communication network is simplified. The power consumption information transmission efficiency is improved.