Abstract: In order to study airflow characteristics of network fire,a network fire simulation and small size experimental table were built. This table consisted of one fire branch and two lateral branches.According to different combination modes of lateral branch length and the initial wind speed,seven simulation tests were carried out.The airflow reversal of lateral branch was monitored with hot-wire anemometers and tracer technology.The results showed that the criterion obtained by non-steady-state analysis method was reasonable.