The invention discloses a merchant advertisement promotion method and system for multi-platform information sharing. The method comprises the steps of receiving advertisement information and award information input by a merchant, and generating an incidence relation; storing the award information, and displaying the advertisement information on a system interface; when a user selects a piece of advertisement information on the system interface and forwards the advertisement information to a third-party platform, automatically generating an award relation of a random amount of money to an account of the user according to the incidence relation and the award information; storing a user financial record, increasing the balance of the user, and reducing the merchant award balance correspondingly. The system comprises a user interface, a platform interface, a processor, a memory and a computer program which is stored in the memory and can be executed on the processor; the user interface isused to receive merchant information and user information; the platform interface is used to achieve docking of the system and the third-party platform; the processor achieves the method when executing the computer program, and thus advertisement promotion points to the user who has a purchase intention to the advertisement merchant more precisely.