Abstract: It has been shown that the genetic mechanism of collapses is one of the key problems for urban-ground-collapse-research. The data has been based on the case of urban-ground-collapse reported in 2014 to 2015. The method of statistical analysis was used to get the characteristics and causes of ground collapse. According to the formation mechanism, the urban ground collapses which weren't caused by grottoes are classified. They are suffusion collapse, scour-burst collapse, vacuum suction type collapse, loose soil creep collapse.