For the asymmetry and poor consistency of recovery pressures in the two receiving cavities of deflector jet servo valve，flow field simulation model considering the size and shape error of the jet-pan was established and the relationship between the shape factors of the jet-pan and the pressure characteristics was studied by using multi-ple linear regression analysis． The neural network algorithm was used to predict the recovery pressure of jet-pan components under different size and shape error combinations，and the shape factors distribution which cause the pressure difference excess was studied as well． Ｒesearch shows that the main factors affecting the recovery pressure include the width of wedge，the width of jet orifice，the thickness of jet-pan，the round corners of receiving cavities and the symmetry of wedge． And the main factors of the pressure difference between the two cavities are the symme-try of the wedge，the verticality of the jet orifice，the symmetry of round corners and the inner angle of the receiving cavities． The pressure difference between the two cavities is in normal distribution． The pressure difference excess is caused by the combination of several factors，but even if all the shape factors meet the design requirements，the pressure difference excess may occur． Experimental results agree with the theoretical results．