Future communication systems might be characterized by an integration of multiple access systems, and people are expecting excellent multi-access solutions for better services. However, currently proposed solutions in different layers are unable to completely fulfill the requirements. In this paper, we put forward the stream control transport protocol (SCTP) as a transport layer approach for multi-access, and propose an efficient SCTP load-sharing enhancement. The evaluation of performance has been investigated in the key multi-access scenarios with theoretical analyses, simulations in NS and some Linux-kernel experiments. Since SCTP supplies an effective multi-homing mechanism and the transport layer solutions for multi-access can quickly adapt to the fluctuating network conditions, our SCTP approach is able to bring more throughput for the simultaneous multi-access perform seamless behavior during the vertical handover between heterogeneous access networks, and provide better robustness and connectivity than other solutions in the wireless multi-access scenarios.