Using the hydrolyzed animal protein（HAP） of pork as materials， four thermal reaction products （TRPs） including only HAP， HAP with xylose（HAP-Xyl）， HAP with oxidized lard （HAP-OL）， and HAP with both oxidized lard and xylose（HAP-xyl-OL）， were prepared. According to UV-Vis absorbance values at 420 nm， browning degrees， and pH decrease of the final reaction solutions， it was found Xyl contributed rather more on browning than OL in the reaction with the HAP. On the other hand， though both Xyl and OL increased taste properties of umami， meat broth， kukumi， continuity and mouthfulness of the reaction solutions， Xyl preferred to increase umami taste and meat broth taste， while OL preferred to increase the kukumi and continuity and mouthfulness taste properties. Except for the TRP of only HAP， all the other three TRPs were all ultrafiltered with taste-active fractions （MW<1 ku） collected. The collected MW<1 ku fractions were separated by G-15 Sephadex column chromatography with 12 taste-active sub-fractions collected. Three strong taste-active sub-fractions were separated by reversed phase high-performance liquid chromatography（RP-HPLC） while 9 taste-active sub-sub-fractions collected. Finally， two sub-sub-fractions， which showed more pure than the others， were analyzed by MALDI-TOF-MS/MS. As a result， three peptides were identified from the two sub-sub-fractions.