The invention relates to a device utilizing RS232 interfaces to realize one-to-many data transmission and a data transmission method of the device. The device comprises a main control board and n data acquisition boards connected with the main control board. The device is characterized in that the main control board is connected with a main control RS232 interface circuit, the n data acquisition boards are all connected with an acquisition board RS232 interface circuit, the n data acquisition boards are connected with the main control RS232 interface circuit respectively through the acquisition board RS232 interface circuit connected with the n data acquisition boards, and finally the n data acquisition boards are connected with the main control board. Compared with the prior art, the device utilizing the RS232 interfaces to realize one-to-many data transmission and the data transmission method of the device have the advantages that software and hardware implementation methods for using the RS232 interfaces to realize one-to-many high speed data transmission are provided; the hardware implementation method has the advantages that the interfaces are simple, the universality is strong, the hardware is stable and reliable, high speed transmission can be realized with the baud rate reaching 2Mbit/s, serial ports are strong in load carrying capacity, and one-to-sixteen communication can be realized; according to the software implementation method, a serial port idle time threshold value is set so that bus conflict can be effectively prevented, and the system stability is improved.