Abstract: A new method has been elaborated to predict the burst speed of aeroengine disks.The disks should overspeed or even break due to malfunction of control system,shaft decoupling or afterburning failure.In order to avoid catastrophic failure of an engine,it is required to allow a margin of the disk burst speed.When the maximum rotor speed approaches to the disk burst speed,the plastic strain attains to large value in strain hardening range.So the concepts of material and geometrical nonlinearities are employed,but it is very difficult to obtain the solution of the double nonlinear problems.An approximate large deformation large analytical method is proposed firstly.The basic equations are derived according to the variable thickness and temperature of the disks.Secondly,the computational procedure is described and the burst speeds of four tested disks are obtained from the calculations.At last,the calculated results are compared with the test data,and the differences are less than four percent.Therefrom,it is proved that the new method is simple,convinent and accurate for engineering application as well as it is applicable to a wide variety of disks.