Disclosed a method for measuring quality of a Composite Video Broadcast Signal (CVBS). The method includes that: a pre-stored standard video code stream is converted into a CVBS; Analogue-to-Digital (A/D) conversion is performed on the CVBS, and a numerical value corresponding to each line of converted CVBS is stored according to a line-field synchronization signal in the converted signal; and the quality of the CVBS is calculated according to the stored numerical value corresponding to each line of CVBS. Also disclosed is a device for implementing the method and a storage medium.