Aiming at the problem of fuel-optimal control of hypersonic vehicles (HSV) in the ascending stage, a trigonometric regularization method is introduced based on the optimal control indirect method. This method makes up for the shortcoming of the indirect method: The derivation of the first-order optimal necessary condition for complex optimal control problems is cumbersome, singular optimal problem is difficult to solve and the optimal control is unsmooth. Aiming at the problem of divergence due to the improper initial costate variables guess in the two-point boundary value problem(TPBVP) transformed the indirect method, the continuation method is introduced and improved. The method uses the solution of the simplified problem as the initial value of the continuation, and through solving a series of TPBVP, approximates to the solution of the original problems. The simulation results show that through the above methods, the fuel-optimal control problem of HSV in the ascending stage under the complex model can be solved reliably.