This paper considers the trajectory optimization of entry vehicles using convex programming. Optimal entry trajectory satisfying path constraints on heating rate, dynamic pressure, and load factor is btained with sequential second-order cone programming (SOCP). The nonlinear dynamics and path constraints are simplified by changing the independent variable into energy. To mitigate infeasibility and solution divergence problems, the post-correction technique is utilized as well as slack variables and trust-region. The step length of obtained solution at each iteration is modified based on the amount of linearization error. The robustness and effectiveness of the proposed method is demonstrated through numerical simulation.