The invention discloses a data transmitting method and system between airplane and ground system, which comprises the following parts: data pack processing mode, buffer area mode, flow engine mode, memory management mode and data transceiver mode. The transmitting method comprises the following steps: packing the received original flight data to form data pack; reserving the data pack according to the transceiver sequence; dividing the data pack into multiple data pack queues; attaching frame head, data starting mark and checking code on the data pack queue to form information frame according to the data pack queue sequence; transmitting the information frame. The invention realizes high flow communication between airplane and ground system, which solves the buffer problem of data under high flow effectively.