It was observed that hydrazine could enhance the chemiluminescence (CL) intensity of tris-(1,10-phenanthroline) ruthenium (Ⅱ) ( Ru (phen)3 2+ )- Cerium (Ⅳ) ( Ce (Ⅳ) )system, based on which, a novel CL system, Ru(phen)32+-Hydrazine-Ce(Ⅳ), was established. This CL system was investigated and employed to detect hydrazine. Under the optimum experimental conditions, the linear range and detection limit of the proposed method are 2.0×10-6-2.0×10-3g·L-1 and 1.8×10-6 g·L-1,respectively. For 1.5×10-5, 1.5×10-4 and 1.2×10-3 g·L-1 hydrazine, the relative standard deviation (RSD) is 2.9%, 2.2 % and 3.1%,respectively (n= 11). The proposed method has been used to detect the content of hydrazine in the synthetic samples with satisfactory results.