In the exploration activities of target celestial bodies that may contain life，it is necessary not only to meet the requirements of planetary protection policies that have been established both domestically and internationally，but also to find the optimal balance among the engineering development progress，cost，and scientific resarch effectiveness.In this paper，the compatibility of the development process of existing deep space exploration missions and various planetary protection tasks are studied.Taking the strictest V-class restricted return mission as an example，the advancement process of five stages for the planetary protection work is sorted out，and the key measures are identified.The results show that there is a strong coupling relationship between the high-grade planetary protection work and the development of spacecrafts，which will seriously slow down the entire engineering development schedule and increase the engineering development cost.To achieve a better balance among the schedule，cost，and effectiveness and avoid the occurrence of cross biological pollution events between the target celestial bodies and the Earth，the entry point of the planetary protection work in the development of deep space exploration missions should be reasonably planned，and the key technologies for planetary protection should be improved and optimized.