To satisfy the rigorous constraint of energy balance, near-space solar aircrafts are usually designed with large aspect ratio and lightweight structures, which leads to a very slow airspeed and a bad flight safety in low altitude airspace. For matching the aerodynamic performances at nearspace working point and in low-altitude climbing process, a climbing approach of solar aircraft based on active morphing was proposed. The aerodynamic and propulsion modeling methods were researched. The flight safety and maneuverability of the pitch, roll and yaw attitude channels were analyzed in quantification. As a result, a climb process with the wing gradually stretching was decided, in which the level flight thrust and power costs were checked. Results show that the stability and maneuverability in low altitude flight are effectively improved, and the cost of power is increased by the wing morphing.