Ultrafast relaxation processes and transient two-photon absorption are studied in a novel porphyrin side-chain polymer, 5-hydroxy-10, 15,20-triphenyl-porphyrin-poly(glycidyl methacrylate) (HTPP-PGMA), by using picosecond luminescence spectroscopy and femtosecond pump-probe techniques. HTPP-PGMA exhibits the ultrafast initial luminescence decay (～300ps), which is absent in the conventional porphyrin monomer such as TPP. Enhanced two-photon absorption was observed in HTPP-PGMA; the corresponding Im x(a) is about 2.8× 10-11 esu, which is almost one order of magnitude larger than that of the conventional porphyrin monomer (TPP) (～1.3 × 10-12 esu).The ultrafast energy transfer plays an important role in the excited-state relaxation dynamics observed in HTPPPGMA. The potential application of HTPP-PGMA in optical switching is discussed.