Collagen is one of the main structural proteins in human dermis. The lack and atrophy of collagen induces the appearance of wrinkles and beginning of aging. L-ascorbic acid has significant effects on skin-whitening and anti-oxidation, which helps keep skin beautiful and healthy, respectively. With auto-fluorescence, the amount of collagen is in proportion to the strength of its fluorescence spectrum. Therefore, a new method is proposed to determine the content of collagen and the health of skin through the analysis of fluorescence and reflection spectra. Compared with conventional chemical analysis, this method needs less time, and is much more noninvasive. Solutions of different concentration of external collagen and L-ascorbic acid were applied on healthy, spotted and wrinkled skin in this study. By the time dependence of fluorescence and reflection spectra, the effects of skin absorption and restoration of collagen and L-ascorbic acid were derived, respectively. The experiment shows that the collagen or L-ascorbic acid solution of adequate concentration is best for skin absorption. Admixed with suitable concentration of L-ascorbic acid, the collagen solution was well absorbed and results in effect of smoothing wrinkles; the effect of L-ascorbic acid to clear up the spots was also demonstrated. By scientific explorations shown above, the restoration effects of cosmetic materials were validated, and people’s confusion and myth about skincare products were avoided. Consequently, this study helps advance cosmetic industry.