The implementations of the subject matter described herein relate to communication between field programmable gate arrays. In some implementations, an FPGA device comprises a first protocol stack configured to: receive, from a source application, a data transmitting request for a destination application; package the data transmitting request into a first packet by adding a header to the data transmitting request, the header indicating the source application and the destination application; and transmit a physical address of a second protocol stack connected with the destination application. The FPGA device further comprises a PCIe interface configured to: package the first packet into a second packet based on the physical address of the second protocol stack received from the first protocol stack so that the first packet serves as a data portion of the second packet, the second packet being a TLP conforming to the PCIe standard; and transmit the second packet.