Abstract: The design of LEO（low earth orbit）satellite constellation is the prerequisite and key to deploy LEO satellite network.However，the uneven distribution of ground users and the unreasonable allocation of satellite resources pose a major challenge to the service quality of satellite networks.To solve the above problems，a method of LEO satellite constellation based on QoS（quality of service） was proposed by establishing a QoS metrics system.Firstly，the LEO satellite network model and constellation coverage model were established，and the metric of constellation invulnerability was defined via the building criteria of inter satellite link.Secondly，the resource matching between satellite constellation and target area users was analyzed by establishing user links and defining user matching degree.Following that，the LEO constellation design problem was established to maximize the costeffectiveness ratio under the constraints of QoS metrics.The defined QoS metrics included signal-to-noise ratio，bit error rate，invulnerability，constellation coverage rate and user matching degree.In addition，the orbital parameters of the designed LEO satellite constellation were obtained through the genetic tabu intelligent algorithm.The simulation results show that the proposed LEO satellite constellation design scheme can maximize the constellation cost-effectiveness ratio while meeting the specified QoS constraints.

Key words: LEO satellite constellation design, quality of service, invulnerability, constellation coverage rate, user matching degree, cost-effectiveness ratio