Provided is a method of constructing a sequencing library. The method includes 1) providing a single-stranded DNA fragment from a biological sample; 2) subjecting the single-stranded DNA fragment to whole genomic amplification to obtain a whole genome amplification product; 3) fragmenting the whole genome amplification product using a transposase embedded with two adaptors to obtain a fragmented product with two adaptors respectively at two ends; and 4) amplifying the fragmented product with two adaptors respectively at two ends using a tag sequence and a pair of primers to obtain said sequencing library.