Dear editor,rnThe defending guidance problem for the target-attackerdefender (TAD) scenario is a challenge.The attacker (A) refers to the attacking missile, whose objective is to intercept the target aircraft (T), while the target aircraft is trying to avoid the attacker.The defender (D), namely the defensive missile, aims to intercept the attacker before a collision occurs between the attacker and the target.rnThere has been considerable interests on this subject in the last decade.The guidance laws were developed using optimal theory [1-3] and linear quadratic differential game (LQDG) theory [4].In [5], a geometrically intuitive guidance strategy called line-of-sight guidance law was derived.More recently, nonlinear guidance strategies using sliding-mode control technique have been presented in [6, 7].However,most of the previous work was analyzed in a planar and linearized framework.The perfect information such as the attacker's acceleration and time-to-go are always required,which could not be directly measured.In this study, we present a novel guidance strategy with the iterative computational method to overcome the above-mentioned shortcomings.