The scandium dialkyl complex LSc(CH2SiMe3)2 (L=(2,6-iPr2C6H3)NC(Me)CHPPh2N-(2,6-Me2C6H3)) activated with [Ph3C][B(C6F5)4] could initiate ethylene and propylene copolymerization with high activity (7.5×105g(PE)mol-1 h-1 (105Pa)-1) under the conditions of room temperature (30 ℃) and atomphere pressure (1.0 × 105 Pa).The influence of comonomer feed content and polymerization temperature on activity and the composition of the copolymers using LSc(CH2SiMe3)2/[Ph3C][B(C6F5)4] catalytic system were investigated.An increase in the initial propylene feed content leads to the increase in the incorporated propylene content of the resulting copolymer.At 30 ℃,the highest activity and incorporation of propylene were achieved.Determination of the reactivity ratios shows a much high reactivity for ethylene (rE=29.75 and rP=0.015).The resultant copolymers are elastomers having random sequence distibution of the two monomeric units evidenced by 13C-NMR spectroscopy and DSC analyses.