Solving the traditional estimation of spare part requirement is very subjectivity and is not scientifically, put forward an estimation method based on BP neural network (NN) on the background of field drill of communication army by analyzing the influence factors of field drill. It also introduces spare part precise supporting and requirement estimation and BP NN and their acclimatization, analyses the influence factors of field drill, tests the applicability of the BP algorithm on the former of one transmitter-receiver’s power amplifier. The result shows that the algorithm can greatly improve precision of spare part estimation, also it can meet the need of accurate maintenance support in future warfare.