In order to improve the terminal penetration capability of missiles and ensure the accuracy of maneuvering target attacking,a novel guidance law for missile penetration is proposed.Firstly,an adaptive disturbance observer is developed to estimate the acceleration of target maneuvering.The designed observer can estimate the target maneuvering in finite time without knowing the upper bound of target acceleration in advance.Secondly,a sliding-mode surface is constructed by using the guidance error and the normal maneuvering velocity,and the guidance accuracy is not affected by the additional maneuvering through the maneuvering-attenuation design.Thirdly,based on the estimated target acceleration and the design of continuous penetration maneuvering,the finite-time-convergent guidance law is constructed.The designed guidance law is continuous and can ensure the finite-time convergence of guidance error.Finally,simulation is made considering the offence-defense confrontation between the maneuvering target,the interceptor and the penetration missiles,and the results show that the designed guidance law has high precision and strong penetration capability.