AIM:To investigate the application of Methylrosanilinium Chloride in the diagnosis of fungal keratitis.METHODS:Seventy fungal keratitis cases were collected from January 2009 to December 2010.The corneal scraping specimens were performed Methylrosanilinium Chloride staining and 100g/L KOH wet mount before microscopic observation,fungal culture and strain identification.The cultivation results were regarded as the "gold standard" of fungal keratitis diagnosis.RESULTS:The cultivation results of 58 cases were positive among 70 samples of fungal keratitis,the positive rate was 82.9%.Methylrosanilinium Chloride staining showed the positive rate was 61.4%,sensitivity 67.2%,specificity 29.6%,false positive rate 33.3%,false negative rate 32.8%,the correct index-3.1%,positive predictive value 90.7%,negative predictive value 29.6%.10% KOH wat mount showed the positive rate was 44.3%,sensitivity 44.8%,specificity 17.9%,false positive rate 41.7%,false negative rate 55.2%,the correct index-37.2%,positive predictive value 83.9%,negative predictive value 17.9%.CONCLUSION:Methylrosanilinium Chloride staining is a fast,effective way for the early diagnosis of fungal keratitis.