Anoxic biodegradation batch experiments were conducted to investigate the biodegradation properties of several typical nitrogen heterocyclic compounds, such as pyridine, indole, quinoline, isoquinoline and 2-methyl quinoline in coal coking wastewater. The results showed that all these compounds can be degraded in anoxic condition, and degradation rate of pyridine is far faster than others. QSBR (quantitative structure-biodegradability relationship) studies of the above five nitrogen heterocyclic compounds in anoxic condition show that denitrification rate is correlated well with molecular connectivity index.