With the rapid development of artificial assisted reproduction and bioengineering technology， more and more impacts have been placed on traditional fertility methods. At the same time， the traditional reproductive order is also undergoing significant changes， which has caused a great impact on the traditional family structure， social ethics and legal system. This requires us to attach great importance to this issue in the fields of law， sociology， medicine and so on. We should analyze the function of three?person co?breeding based on the perspective of population construction and the reproductive rule of law， to reasonably regulate and restrict three?person co?breeding so that it can benefit human beings.