The invention provides a protective method for lamps, which comprises following steps: (1) to test if transparent parts are damaged;(2) to automatically cut off working circuit of lamps if damage of the transparent parts is detected. The invention also provides a protective device of lamps, which comprises a transparent part crushing induction device used for sensing and testing if the transparent parts are crushed and a switch control circuit used for controlling electrical circuit of lamps according to signals of the transparent part crushing induction device. The transparent part crushing induction device is electrically connected with the lamps through the switch control circuit. The use of the protective device and the lamps provided by the invention has the advantages of effectively improving the working security of the lamps, effectively protecting the lamps and prolonging the service life of the lamps as well.