A data backup method, comprising: acquiring (S101, S201) remaining storage capacity of a cloud space; collecting (S102, S202) usage characteristic information of an application when the remaining storage capacity is less than a preset value; grading (S103, S203), based on the usage characteristic information of the application, the application to acquire a grade of the application; characterized in the method further comprising: backing up (S104, S205) updated data to the cloud space when the grade of the application is consistent with a preset grade and data in the application is updated; wherein the collecting and grading further comprises: collecting a clicking rate and a running time of the application within a preset time period when the remaining storage capacity is less than the preset value; acquiring type information of the application; and grading the application based on the type information, the clicking rate and the running time of the application, to acquire the grade of the application; wherein the grade of the application is represented by a multiplication of a coefficient corresponding to the type information with a coefficient corresponding to the clicking rate and a coefficient corresponding to the running time. acquiring (S101, S201) remaining storage capacity of a cloud space; collecting (S102, S202) usage characteristic information of an application when the remaining storage capacity is less than a preset value; grading (S103, S203), based on the usage characteristic information of the application, the application to acquire a grade of the application; characterized in the method further comprising: backing up (S104, S205) updated data to the cloud space when the grade of the application is consistent with a preset grade and data in the application is updated; wherein the collecting and grading further comprises: collecting a clicking rate and a running time of the application within a preset time period when the remaining storage capacity is less than the preset value; acquiring type information of the application; and grading the application based on the type information, the clicking rate and the running time of the application, to acquire the grade of the application; wherein the grade of the application is represented by a multiplication of a coefficient corresponding to the type information with a coefficient corresponding to the clicking rate and a coefficient corresponding to the running time. backing up (S104, S205) updated data to the cloud space when the grade of the application is consistent with a preset grade and data in the application is updated; wherein the collecting and grading further comprises: collecting a clicking rate and a running time of the application within a preset time period when the remaining storage capacity is less than the preset value; acquiring type information of the application; and grading the application based on the type information, the clicking rate and the running time of the application, to acquire the grade of the application; wherein the grade of the application is represented by a multiplication of a coefficient corresponding to the type information with a coefficient corresponding to the clicking rate and a coefficient corresponding to the running time. collecting a clicking rate and a running time of the application within a preset time period when the remaining storage capacity is less than the preset value; acquiring type information of the application; and grading the application based on the type information, the clicking rate and the running time of the application, to acquire the grade of the application; wherein the grade of the application is represented by a multiplication of a coefficient corresponding to the type information with a coefficient corresponding to the clicking rate and a coefficient corresponding to the running time.