Inclusion criteria:  Men or female patients older than 20 years old with facial photoaging (Glogau Scale type II) The photoaging severity of bilateral face is symmetric.  Exclusion criteria:  Patients with thrombocytopenia, coagulopathy, hematopoietic malignancy. Patients with severe inflammation over treated area, malignancy, keloid, or poor wound healing history. Patients had received laser, radiofrequency, ultherapy over treated area within 6 months. Patients had received botulism or filler injection over treated area within 12 months. Patients had received plastic surgery over treated area within 12 months. Patients had severe psychiatric disorders with poor control. Patients with other diseases which are not suitable for receiving platelet rich plasma (PRP) injection therapy.