[Objective] The research aimed to study the mycorrhizal formation in the offspring tissue culture seedling bottle of Pinus elliottii with Lecanosticta acicola resistance.[Method] The mycorrhizal formation of Pinus elliottii regenerated plant in vitro was studied,and the growth condition of regenerated plant was observed.[Result] The culture substrate and the inoculation amount of mycorrhizal fungi had the big influence on the mycorrhizal formation in vitro.After the root primordia were induced by Pinus elliottii caespitose shoots,it was best to transplant in the perlite substrate and inoculate Pisolithus tinctorius,which was favorable for the mycorrhizal formation.When the two blocks of Pisolithus tinctorius were inoculated in the perlite medium,the mycorrhizal formation rate reached 84.4%.The dichotomous branching short root was the most,and 12.49 roots were formed in every main root.The mycorrhizal formation improved the survival rate of regenerated plant domestication transplantation.The mycorrhizal regenerated plant grew well in the phytotron,and the root system was developed.[Conclusion] The research provided the basis for improving the survival rate of Pinus elliottii tissue culture regenerated plant with Lecanosticta acicola resistance.