Shenzhen City is a seashore city with axial ridge and low mountain physiognomy to seashore plain from the North to the South. The geological characteristics are of complicate geology,uneven stratum,crushed rock,strong rainfall,ample groundwater and strong tectonism. There are certain slope instability types in Shenzhen City:landslide and collapse arising in shallow loose soil,slope sliding along the consequent faults in soft metamorphosed rock and in mixed rock and sliding being caused by the tectonic hard core of granite. The principles of those diseases can be categorized as follows:(1) most of sliding arises from the correlated impact of rainfall and groundwater;(2) instability is often developed along the south of ridge with the strike direction of EW;(3) landslides and collapse are often developed in soft rock and cracked rock,but landslip and rock fall often in hard rock;and (4) Shenzhen large fault has strong impact on the slope instability,on whose upper bed more instability disasters are developed and vice versa. More instability disasters are developed strongly on the zone of the main NE strike fault intersected with other faults. Though more preventions and new technologies are adopted in slope instability treatment,the progresses of Shenzhen slope instability prevention and control should proceed as follows:(1) the law of “geology is foundation”should be carried out;(2) the new techniques should be adopted;(3) supervision should be enhanced;(4) more attention to should be paid to the research of the effect of treatment measures;and (5) the standards of slope instability prevention and control should be established.