Hydrosilation-curing vulcanizates (HCV) and peroxide-curing vulcanizates (PCV) were prepared respectively by using polysiloxanes containing phenylethynyl groups (PE-PDMS) as cross-linkers. The mechanical properties and average molecular weights of effective units ((M) over bar(c)) of HCV and PCV were measured. The experimental results show that PE-PDMS can be used as cross-linkers of heat-curable silicone rubber instead of C gum, and when adding suitable amounts of PE-PDMS, the vulcanizates exhibited good mechanical properties. The tear strength of some vulcanizates reached 30.0 kN/m, the tensile strength 11.7 MPa, the modulus at 100% extension 3.3 MPa, and the permanent deformation is low. PE-PDMS also has cure retardation to hydrosilation-cure silicone rubber and thus can prolong the shelf time of stocks. (C) 2000 John Wiley & Sons, Inc.