This trial will study the effectiveness of photodynamic therapy with aminolaevulinic acid for the treatment of patients with HPV+ low grade cervical intraepithelial neoplasia (LSIL;CIN1).

Inclusion Criteria:

• Premenopausal women, 25-50 years of age
• Diagnosed with LSIL/CIN1 by local pathology (biopsy) and high-risk HPV positive by HC2 assay within the last 3 months
• Satisfactory colposcopy examination (visibility of entire transformation zone and entire lesion margin )
• Meet the following conditions: pregnancy test negative; no pregnancy plan during the trial; no sexuality or reliable contraceptive measures taken since last menstruation to the onset of the study, agreeing to adopt reliable contraceptive measures during the study
• Written informed consent signed

Exclusion Criteria:

• ASC-H (atypical squamous cells, cannot exclude HSIL) or HSIL (high-grade squamous intraepithelial lesions) or AGC (atypical glandular cells) or AIS (adenocarcinoma in situ) on cytology, or malignant cells on cytology or histology, or other suspicion of either micro-invasive or invasive disease
• Invasive carcinoma possibility or lesions extending to the vaginal vault or suspicion of endocervical disease on colposcopy
• Severe pelvic inflammatory disease, severe cervicitis, or other severe gynaecological infection as per clinical examination
• Undiagnosed vaginal bleeding
• With allergic disease at present; known or suspected porphyria; known allergy to ALA or analogues
• With serious cardiovascular, neurologic, psychiatric, endocrine, hematological disease; immunocompromised conditions; patients with malignant tumors
• Hepatic or renal functions abnormal (alanine aminotransferase or aspartate transaminase or total bilirubin > 1.5 upper limit of normal [ULN], or serum creatinine or blood urea nitrogen > 1.5 ULN)
• Pregnancy or nursing
• Previous physical therapy of LSIL/CIN1 after pathologic diagnosis
• Participation in any clinical studies within the last 30 days
• Subjects that the investigators judged to be not suitable to participate the study besides above