1. A cloud infrastructure-based method for maintenance and deployment of an application system, comprising: obtaining a scheduling deployment policy of an application, wherein the scheduling deployment policy of the application includes determining a division of tasks according to a service feature in order to deploy an application as multiple application instances, and determining a decomposition of an application instance according to a decomposition threshold or a combination of application instances according to a combination threshold; obtaining information regarding performance of an application instance or task processing state data of the application instance; performing application scheduling deployment according to the scheduling deployment policy of the application and the information regarding the performance of the application instance or the task processing state data of the application instance; generating a deployment instruction for the application instance; and completing deployment configuration of the application instance, wherein the deployment instruction comprises an application attribute and a range of attribute values, and wherein deploying the deployment instruction comprises deploying the application as multiple application instances, and dividing one application instance into multiple application instances or combining multiple application instances; wherein the method further comprises: recording the information regarding the performance of the application instance or the task processing state data of the application instance; performing trend prediction for the performance of the application instance according to recorded data, and sending the recorded data and the trend prediction; wherein the method further comprises: sending, corresponding to coding name of the application instance, the information regarding the performance of the application instance or the task processing state data of the application instance; and sending, corresponding to the coding name of the application instance carried in the deployment instruction, the deployment instruction.