A series-type LED lamp strip module includes a first LED lamp strip module and a second LED lamp strip module. The first LED lamp strip module and the second LED lamp strip module both include a power switch controller, at lease one LED lamp strip, a signal output adaptor, a signal input adaptor, a power plug, and a power socket. The power plug of the second LED lamp strip module is inserted into the power socket of the first LED lamp strip module, and the signal output adaptor of the first LED lamp strip module is electrically connected to the signal input adaptor of the second LED lamp strip module so as to connect the first LED lamp strip module and the second LED lamp strip module. In addition, a microcontroller unit outputs a control signal to lighten light emitting diodes in different types to produce multiple brightness variations.