The in-situ chemical preparation technology has been explored for the first time for large size high polarization polymer photonic crystal fibers (pPCFs) preforms. The optimal polymerization conditions have been investigated. From experiments of the secondary draw-stretching of the preforms and the measured results such as microstructure,transmittance,glass transition temperature (Tg),molecular weight and so on,it is found that these preforms have a lot of characteristics,i. e. steady mechanics structure,higher optical transparency,and the pPCFs made by these preforms have ideally microstructure retaining,less holes collapse-rate,and lower non-intrinsic loss. If laser dyes and rare earth chelates were mixed into reaction system,the high polarization pPCFs preforms with fluorescence can be gained,which will be a new materials for development of the polarization maintaining PCF lasers.