In order to achieve complementary advantages and information sharing of heterogeneous workflow systems among enterprises, concerning the workflow showing heterogeneous distribution and other characteristics, an interface design of heterogeneous workflow processes interconnection based on Web service was proposed. For the interconnection of heterogeneous processes, the solution of heterogeneous workflow interconnection was described from call interface，call mode and call return respectively. Taking example of SynchroFlow workflow process described by XPDL and ODE (Open Dynamic Engine) workflow process described by BPEL, the process calls between the workflows was achieved.