A flow injection method is described for the determination of adenosine 5-triphsophate using immobilized alkaline phopsphatase based on luminal chemiluminescence detection. The molybdophosphoric heteropoly acid formed by phosphate and ammonium molybdate in acidic condition generated chemiluminescence emission by the oxidation of luminal. The detection limit (2s) was 1.0 x 10-7 M with a sample throughput of 45 h-1. The calibration graph was linear over the range 2.0-10 x 10-6 M (r2= 0.9987) with relative a support for alkaline phosphate immobilization and the immobilized enzymes showed good stability, and no deterioration in enzymes activity was recorded after use for three months.