The invention provides a rapid 
trajectory optimization method of a 
rocket power lowering landing process, discloses a fuel optimal power lowering landing rapid 
trajectory planning method, and belongsto the field of 
rocket guidance. An implementation method includes the steps that dynamics modeling and dimensional normalization are conducted on power lowering flying, and a three-dimensional dimensionless dynamics equation is established; an independent variable of the dynamics equation is changed from the time to the height; by introducing constraints required for power lowering flying, an 
optimal control problem of fuel optimal power lowering landing is established; a nonlinear dynamics equation in the original 
optimal control problem is treated as a linear dynamics equation; a part of the nonlinearity is retained and transformed into a constraint, a non-convex constraint is convexified, and a convex 
optimal control problem is established; the convex optimal control problem is discretized at non-uniform 
discrete points by using a four-order Runge-Kutta method, and a second-order 
cone programming problem is established; and the second-order 
cone programming problem is solved iteratively until converging, and 
trajectory planning of power lowering landing flying can be achieved. According to the rapid 
trajectory optimization method, the 
advantage of high efficiency is achieved, and the safety and the reliability of landing of the 
rocket power lowering stage can be improved.