Abstract: The present experiment was conducted to determine the effects of tannin content in residue of tealeaves(RTL) on digestion and utilization of nutrients and metabolic parameters of nitrogen in sheep. The contents of nutrients and tannin in RTL were analysed; The in vitro degradability（rdDM、tdDM、rdCP、tdCP） of dry matter(DM) and crude protein(CP) of mixtures with six ratio of RTL to soybean meal（0:10, 1:9, 2:8, 3:7, 4:6, 10:0 ）, which levels of RTL condensed tannin( RTLCT) of the mixtures were 0.00, 0.16, 0.31, 0.47, 0.63, 1.57 g·kg- 1DM, respectively, was measured by incubating in rumen fluid and rumen fluid + HClpepsin. To study the effects of RTLCT contents on digestion and utilization of nutrients and metabolic profiles of nitrogen in sheep, four High Mountain Finewool wethers (one and a half years old and average live weight of (29±2.55)kg) fitted with permanent rumen fistula and a 4×4 Latin square design with four cycles of diet each of 9 d for preliminary followed 6 d for sampling were used in this experiment. The contents of RTLCT in diets were 0.00(A), 0.77(B), 1.53(C), 2.30(D) g·kg -1DM . The results showed that: (1) the range of contents of CP, crude fiber(CF), TAE(tannic acid equivalent) and CT in three samples of TRL were 23.23%28.11%, 16.68%17.84%, 1.98%2.10%, 1.47%1.57%, respectively. (2) The degradabilities of DM and CP of the mixtures in rumen fluid and rumen fluid + HClpepsin(rdDM, tdDM, rdCP, tdCP) decreased linearly as the contents of RTLCT , the range of change were 61.39%25.67%, 79.61%26.47%, 60.76%16.68%, 84.85%17.69%, respectively. (3) In vivo, the intake of diet was affected by highraito of RTL, compared with diet A and B, the intakes of DM and organic matter (OM) of diet C (P>0.05) and diet D (P<0.01) were lower; the digestibilities of DM, OM, calcium (Ca), phosphorus (P), neutral detergent fiber (NDF) and acid detergent fiber (ADF) of diets were unaffected by the contents of RTLCT(P>0.05). But the excretions of urinary nitrogen were decreased linearly and retention of N increased as the RTLCT level, the retention of nitrogen of diet B, C, D were raised by 12.57% （P>0.05）, 23.61%（P<0.05） and 15.88%（P>0.05）than for diet A, respectively; there were no significant changes of the levels of pH and total nitrogen of rumen fluid (P>0.05) as the levels increasing of RTLCT, while the contents of NH3N and plasma urea nitrogen(BUN) linearly decreased, the levels of NH3N and BUN of diet C and D were 50.36 %(P>0.05) , 46.55%（P<0.05）and 68.04%, 59.99%（P<0.05）lower than that of diet A, correspondingly. It follows that residue of tealeaves were a matter with highprotein, lowfiber and middle content of tannin; under the condition of this experiment, the in vitro rdCP were decreased by RTL CT, but the digestibilities of CP in total gastrointestinal tract were unaffected by levels of RTLCT, and N retentions were increased owing to reducing of the excretion of N in urine as RTLCT; yet high ratio of residue of tealeaves in diet resulted in lowing of intake by sheep. Obviously, the protection effect of RTLCT with 1.53 g·kg- 1DM on protein was better, but no significant effect on the intake of diet.