In this study, Spirulina extract and photodynamic therapy of acne improvement using the search and the absorbance of extracts of Spirulina and P. acnes bacteria growth inhibition experiments, and through clinical trials to improve acne photosensitizer effective. As aresult, Spirulina extract was higher in the absorbance of 626 nm, 406 nm appeared in the most highly photosensitizer photodynamictherapy with the appropriate wavelength ranges that are verified material. In the experiment, the effect of antibacterial antibiotic did notappear photodynamic therapy for acne improvement will be the photosensitizer verified. Photodynamic therapy of P. acnes on the growth inhibition test 5 mg/ml 100% in 2 hour strain were not detected. 10 mg/ml 100% of the 1 hour strains were killed, 50 mg/ml strains of100% in 0.5 hours and were killed. Therefore, spirulina extract alone than photodynamic therapy photodynamic therapy using natural photosensitizer improvement of acne on the skin more effectively verified (Salon skin care & Medical skin care) in the field of safe and effective natural photo sensitizer photodynamic therapy plus radiation therapy for acne skin care, and the case presented.