In this paper, the study on family collection, gene mapping, gene identification and gene function of human genetic diseases carried out in the National Laboratory of Medical Genetics of China, were described in detail. Using G-banding technique a marker chromosome t (1; 3) (q44; p11) associated with nasopharyngeal cancer was found in 1975 at first, and human TDF gene was mapped to chromosome Yp11. 32 in 1981. Since 1991, 590 families with 345 kind of genetic diseases were collected. In 1998, GJB3, a human genetic neurological deafness gene, was identified using a novel strategy of “Gene Family-Candidate Disease Gene Cloning”，and the paper was published in Nature Genetics (20： 370). In 1999, by linkage analysis and Genome Wide Scanning, a locus responsible for disseminated superficial actinic porokeratosis (DSAP) was identified at Chromosome 12q23. 2 - 24. 1; and at the same year a novel protein trafficking gene was also cloned from gene function study.