To solve the reducing problem of soil strength caused by large pores and high compression, the paper used palm to mix in shanghai clay to improve its strength,and selected palm reinforcement rate，reinforcement size as influence factors and did direct slow shear test, CBR test and unconfined compressive strength test . The results showed that palm reinforced soil can significantly improve shanghai clay shear strength, compressive strength and resistance deformation ability. The optimum size of palm reinforcement is 6mm × 12mm. The best reinforcement rate of direct slow shear test is 0.6%.The best reinforcement rate of CBR and unconfined compressive strength test is 0.8%. At the same time, Through the analysis of change reasons of palm reinforced shanghai clay, the paper mastered the change rule of influence of palm reinforced shanghai clay.