An instant messaging method oriented to third-party applications, comprising: registering, when a third-party application is started, the third-party application on an instant messaging open platform through an application identifier and a Software Development Kit component obtained previously through an application from the instant messaging open platform; and providing, by the instant messaging open platform, an open Application Programming Interface interface for the registered third-party application, and performing information transmission with the third-party application through the open API interface; wherein the step of registering, when the third-party application is started, the third-party application on the instant messaging open platform through the application identifier and the SDK component obtained previously comprises: starting the SDK component obtained previously when the third-party application is started; and registering, through the SDK component, the application identifier of the third-party application obtained previously and a logo icon in a preset storage area of the instant messaging open platform; wherein a program of the third party application is installed on an instant messaging mobile terminal on which the instant messaging open platform is implemented; wherein the step of performing, by the instant messaging open platform, information transmission with the third-party application through the open API interface comprises: when the third-party application needs to perform information communication with the instant messaging open platform, caching information content to be sent in a preset storage area of the instant messaging open platform, and starting the instant messaging open platform through the SDK component; and reading, by the instant messaging open platform, the content in the preset storage area, determining whether a new third-party application exists, and if yes, saving the application identifier and the logo icon of the third-party application; and further determining whether information content to be displayed of the corresponding third-party application exists in the preset storage area, and if yes, transmitting the content to be displayed to a user group associated with a local terminal. registering, when a third-party application is started, the third-party application on an instant messaging open platform through an application identifier and a Software Development Kit component obtained previously through an application from the instant messaging open platform; and providing, by the instant messaging open platform, an open Application Programming Interface interface for the registered third-party application, and performing information transmission with the third-party application through the open API interface; wherein the step of registering, when the third-party application is started, the third-party application on the instant messaging open platform through the application identifier and the SDK component obtained previously comprises: starting the SDK component obtained previously when the third-party application is started; and registering, through the SDK component, the application identifier of the third-party application obtained previously and a logo icon in a preset storage area of the instant messaging open platform; starting the SDK component obtained previously when the third-party application is started; and registering, through the SDK component, the application identifier of the third-party application obtained previously and a logo icon in a preset storage area of the instant messaging open platform; wherein a program of the third party application is installed on an instant messaging mobile terminal on which the instant messaging open platform is implemented; wherein the step of performing, by the instant messaging open platform, information transmission with the third-party application through the open API interface comprises: when the third-party application needs to perform information communication with the instant messaging open platform, caching information content to be sent in a preset storage area of the instant messaging open platform, and starting the instant messaging open platform through the SDK component; and reading, by the instant messaging open platform, the content in the preset storage area, determining whether a new third-party application exists, and if yes, saving the application identifier and the logo icon of the third-party application; and further determining whether information content to be displayed of the corresponding third-party application exists in the preset storage area, and if yes, transmitting the content to be displayed to a user group associated with a local terminal. when the third-party application needs to perform information communication with the instant messaging open platform, caching information content to be sent in a preset storage area of the instant messaging open platform, and starting the instant messaging open platform through the SDK component; and reading, by the instant messaging open platform, the content in the preset storage area, determining whether a new third-party application exists, and if yes, saving the application identifier and the logo icon of the third-party application; and further determining whether information content to be displayed of the corresponding third-party application exists in the preset storage area, and if yes, transmitting the content to be displayed to a user group associated with a local terminal.