For the low-speed helicopter satellite communication link with burst mode， there are periodic rotor blade blockage， large Doppler dynamics and low signal-to-noise ratio， which pose a huge challenge to demodulation. It is necessary to study the burst demodulation technology with high performance and low complexity. Based on the decentralized pilots frame structure， a code-aided demodulation method is proposed. First， different frequency offsets are pre-compensated by zones. Then， the burst acquisition of joint Doppler rate estimation is carried out. Finally， the best demodulation branch is selected according to the statistical characteristics of decoding soft output. The simulation results show that， under a given channel model， the demodulation threshold is only increased by 1.5 dB compared with the theoretical performance of unobstructed additive white Gaussian noise （AWGN） channel. Compared with the typical performance of slot transmission， the forward link loss is reduced by 1.5 dB and the return link loss is increased by 0.2 dB.