Abstract： Aminolevulinic acid-based photodynamic therapy (ALA-PDT) has been extensively applied in dermatology.However,the low permeability of ALA across intact skin has limited the efficacy of ALA-PDT.To enhace the percutaneous penetration of ALA,esterified derivatives,microneedles,laser,iontophoresis,delivery vehicles have been used in succession,and some achievements have been made.These methods can increase the transdermal delivery of ALA in terms of depth and quantity by different mechanisms,and indirectly promote the efficacy of ALA-PDT in dermatoses.