The invention provides an anti-theft method and client for a mobile terminal. Wherein, the anti-theft method for a mobile terminal comprises: receiving a background anti-theft opening instruction from a server, wherein the background anti-theft opening instruction carries verification information of the mobile terminal; parsing the background anti-theft opening instruction, obtaining the verification information and performing verification; and opening the anti-theft function in the background according to the background anti-theft opening instruction if the verification is passed. The embodiment of the invention can open the anti-theft function of a mobile terminal after the mobile terminal is lost, and then perform a corresponding anti-theft operation according to an anti-theft instruction, which achieves the beneficial effects of guaranteeing the security of the mobile terminal and fighting against theft crimes more reasonably and effectively.