Near Earth Asteroids have a possibility of impacting the Earth and always represent a threat.This paper proposes a way of changing the orbit of the asteroid to avoid an impact.A solar sail evolving in an H-reversal trajectory is utilized for asteroid deflection.Firstly,the dynamics of the solar sail and the characteristics of the H-reversal trajectory are analyzed.Then,the attitude of the solar sail is optimized to guide the sail to impact the target asteroid along an H-reversal trajectory.The impact velocity depends on two important parameters:the minimum solar distance along the trajectory and lightness number of the solar sail.A larger lightness number and a smaller solar distance lead to a higher impact velocity.Finally,the deflection capability of a solar sail impacting the asteroid along the H-reversal trajectory is discussed.The results show that a 10 kg solar sail with a lead-time of one year can move Apophis out of a 600-m keyhole area in 2029 to eliminate the possibility of its resonant return in 2036.