Aimed at standard trajectory guidance for reentry of the Common Aero Vehicle (CAV), a new longitudinal trajectory guidance law was put forward based on the fuzzy sliding mode control. The longitudinal kinematical equation was reduced according to the characteristics of the CAV state model and the design requirements of fuzzy system. A control law combining fuzzy approximation with switching control was designed to approximate the bank angle's increment and compensate for the approximation error. Simulation results proved that the scheme could implement precise tracking to the longitudinal trajectory with good robustness and real-time performance.