The invention provides a method and system for analyzing alarm correlation based on network and time. The method comprises the following steps: normalizing and converting all alarms in a unified format; and grouping the alarms in accordance with network correlation and on the basis of network configuration information; performing window inspection on each alarm group in accordance with time correlation and analyzing the alarm groups exceeding a time widow; and carrying out pattern matching analysis on alarms with an improved event tree model, and releasing root alarms. According to the invention, the problem that an existing system cannot perform comprehensive analysis can be solved, and the exact and efficient alarm correlation analysis is realized.