Abstract: Fractal modulation based on multiwavelet is proposed and its power density spectrum is calculated and also its bit error ratio under binary data is calculated. Multiwavelet fractal modulation provides more sub-bands and holds more users at each scale and has much higher band efficiency than that with single wavelet. The bit error rate under additive white Gaussian noise channel, Rayleigh channel and multi-path channel is simulated. The systems anti-multi-path fading ability is analyzed by the periodic auto-correlation function of multiwavelets and wavelets. According to the number of the zero point of the periodic auto-correlation function, the capacity can be improved by orthogonal shift and overlapping in time domain.