This paper focuses on the optimization and guidance problem of ascent trajectory, and adopts a sequential convex optimization algorithm with online implementation potential to solve the three degree of freedom precise ascent trajectory problem considering resistance in the case of terminal time freedom. By introducing a time factor, the final time free optimization problem is transformed into a fixed time interval problem. Under the condition of satisfying the six element constraints of the terminal orbit, the dynamics model and thrust control constraints are linearized and discretized. Trust region constraints and virtual control constraints are introduced into performance indicators to obtain a series of convex second-order cone programming subproblems. At the same time, using discrete node value recursion for initial value guessing to solve the sequence convex optimization subproblem until convergence, the accuracy of orbit insertion and computational time are verified through computer simulation, indicating that it is suitable for practical engineering applications.