The invention relates to novel carbene ligands and their incorporated monomeric and resin/polymer linked ruthenium catalysts, which are recyclable and highly active for olefin metathesis reactions. It is disclosed that significant electronic effect of different substituted 2-alkoxybenzylidene ligands on the catalytic activity and stability of corresponding carbene ruthenium complexes, some of novel ruthenium complexes in the invention can be broadly used as catalysts highly efficient for olefin metathesis reactions, particularly in ring-closing (RCM), ring-opening (ROM), ring-opening metathesis polymerization (ROMP) and cross metathesis (CM) in high yield. The invention also relates to preparation of new ruthenium complexes and the use in metathesis.