The invention relates to a kit and a method for detecting VZV infection in a trace biological sample of an eye, and relates to a molecular detection technology for eye viral infections, in particularto a method for extracting DNA from the trace biological sample, wherein the trace biological sample refers to a liquid sample with a volume not exceeding 10mu l-200mu l or a solid sample with a volume not exceeding 1mm<3>. By use of the extracted DNA as a PCR detection template, the eye viral infections can be detected with an accuracy of 80% or more, and the method provides a reliable basis forsubsequent appropriate treatment methods and reduces the blindness of the treatment methods.