The invention discloses a UART communication method and system. The method comprises the steps that if two MCU needing data communication support 7-data-bit UART and 8-data-bit UART respectively, UART parameters of the two MCU are configured to be 8 data bits, and no verification is needed; if communication data needing to be sent by the transmitting end MCU include 7 data bits, the transmitting end UART calculates data of the 7 data bits, 1-bit inspection data is obtained, and after the inspection data is added to the communication data, the communication data is sent; after the receiving end UART receives the communication data containing inspection data, the inspection data is used for inspecting the data-bit data of the communication data; after inspection is passed, the data-bit data is processed into valid data. Accordingly, the MCU can support 7-data-bit UART and 8-data-bit UART at the same time, and the universality is achieved.