The present invention discloses a multi-system compatible modem device, which relates to medium-capacity scatter communication equipment and large-capacity scatter communication equipment in the communication field. The multi-system compatible modem device consists of components such as an auxiliary multiplexer, an auxiliary demultiplexer, a modulator, a demodulator, an intermediate frequency amplifier, a monitor and a power supply. The service rate of the multi-system compatible modem device is compatible with 64kb/s, 128kb/s, 256kb/s, 512kb/s, 1024kb/s, 2048kb/s, 4096kb/s and 8448kb/s, and a self-adaptive balanced demodulation system with stronger anti-multipath ability and distortion adaptive technology with channel fading resistant ability are adopted to realize the aim of scatter communication of tropospheres. The multi-system compatible modem device also has the advantages of constant envelope, narrower signal frequency spectrum, high integration degree, simple and convenient operation, steady and reliable performance and so on, and is particularly suitable to be used as a medium-capacity scatter communication device or a large-capacity scatter communication device in a point-to-point troposphere scatter communication system with frequency division multiple access.