Abstract: There are a lot of uncertain factors in the optimization design of waxy crude oil gathering and transportation pipeline network. The traditional parameter optimization design is usually carried out under deterministic conditions, so it cannot reflect accurately the effects of the fluctuation of physical property parameters, environmental parameters and operational parameters on the design results. In this paper, a mathematical model based on fuzzy reliability constraints for the parameter optimization design of gathering and transportation pipeline network was established according to the theories of probability statistics and fuzzy mathematics while consideration is given to both reliability and economy of gathering and transportation pipeline network. By virtue of this model, the parameters of the pipeline network with dendritic wellhead heating oil gathering process was optimally designed with the pipeline network investment minimization as the object. It is indicated that the optimization design model can not only guarantee the operation safety of the gathering and transportation pipeline network, but also make the optimization result more reasonable. After the optimization, the investment is saved by 11.47%. This method provides a new idea for the parameter optimization design of waxy crude oil gathering and transportation pipeline networks.